St. Thomas, awesome as always. Would like your comments.

Lectio 1. In his prooemium, St. Thomas provides a division of the sciences with an eye to discussing the division of philosophia moralis. What is interesting is that this division follows upon four kinds of order related to mind, two of which are found, and three of which are made, (the order of things, the order of the mind’s acts, the order made in human acts, and the order made in exterior things—hence, since logic is in a way an art and a science, but more of an art, this seems to be an order that is found and made). Hence, since ratio is a natural power that seeks order, it is perfected according to these orders. However, these perfections are the excellences of various sciences. Hence a division of the sciences results. This is related to the division provided in De Trinitate. In that place, St. Thomas begins by dividing the speculative from the practical sciences based upon the intellect’s relationship to truth: either in itself or for the sake of something. However, the mind insofar as it is related to order is also a division according to truth, for this order is always in a “thing” to which the mind is adequated (even in rationalis philosophia, namely second intentions). Hence, one can relate what St. Thomas here calls naturalis philosophia to the three speculative sciences, and the practical sciences to philosophia moralis and artes mechanicas. Also, the division of the sciences based upon the ways in which the mind is related to order fits with the further division of the speculative sciences, for the mind insofar as it is perfected by being adequated to such order receives that order according to its mode of receiving, namely immaterially. However, this immaterial reception is ‘graduated’ into degrees which follow the immateriality present in the things in which said order resides.

Lectio 2. St. Thomas resolves the demonstration that there is a best end [optimum finem] in human affairs to the First Mover, “quia naturale desiderium nihil aliud est quam inclinatio inhaerens rebus ex ordinatione primi moventis, quae non potest esse supervacua.” What implication does this have for the Fifth Way as compared to the First Way? What implication does this have for scientific accounts of the natural law?

Lectio 3. The observation that “auditor bene disciplinatus nec debet maiorem certitudinem requirere nec minori esse contentus quam sit conveniens rei de qua agitur,” in the place where Aristotle is discussing the qualities required of a student of ethics, given the mode in which ethics must proceed (I.3), when put in conjunction with St. Thomas’ analogy of the matter proper to various arts, seems to offer an argument that every science has its own “sapiential part.” For if the good auditor of any science must know the limits of the matter dealt with in the science, he participates in the architectonic office, for the sapiential office holder must inspect the matter in order to use it to his own ends. (It is finely put by St. Thomas where he states the two requirements of an architectonic as that it command the lower, and use them to its own ends. Also finely put is the example St. Albert the Great provides of the various modes in which various arts use their respective matters: "sicut forma hominis in auro per liquefactionem, sed in cera per molliationem, in lingo per decavationem." So just as a rhetorizing mathematician and a mathematizing rhetorician are improper modes, so also attempting to soften gold will not be sufficient, and melting wood will be too extreme, when one is attempting to craft an imitation of the human body.)

This is paper that I wrote for a couple of classes last semester. So far it has been warmly appreciated by the ones who have reviewed it and I am thinking about submitting a modified version for my writing sample to doctoral programs. I realize that it is rather long, but if you get the opportunity to read it I would appreciate your criticisms and comments.



Introduction


Thomas Nagel's influential article, What is it like to be a bat? poses a standard by which all other discussions about the mind-body problem must now be measured. His straightforward and honest critique of reductionism as it is now pursued, especially in the mind-body problem, opens up pathways for dialogue on this matter which formerly might not have been admitted. An important aspect of his article is what he calls a “speculative proposal.” It is here he that suggests another way to bridge the gap between subjective and objective. This solution relies on developing a new phenomenology that would allow us to describe mental events with new concepts.[1]

The enunciation of this difficulty, namely the gap between subjective and objective, is a relatively recent occurrence in the world of philosophy. Nevertheless, the problem though differently formulated in ages past, has been present from the beginning of philosophical inquiry. Classical thought framed this question by asking something like the following: “How do we know things?” or perhaps more pointedly, “How do we know natures?”[2] Prominent among such philosophers is Aristotle, who established a nuanced epistemology which at once allowed for knowing things, and yet respected the limits of our knowledge. St. Thomas, taking Aristotle's lead, establishes an even clearer description of how we know the natures of things and this largely in his historic work De Veritate.

Now the classical formulations betray a very different sort of hermeneutic than what we are confronted with in Nagel's question. The philosophies of Aristotle and St. Thomas have traveled over great distances and times, and are perhaps seen as strangers to the contemporary discussion. It is necessary for us, therefore, to at once respect the differences of the authors and not assume that all are on common ground, and yet to bring these minds together in a productive way that will shed light upon the question at hand. Therefore, this paper will not be a refutation of any one position, but rather we will bring in classical thoughts for the explanatory power of some of their positions, and then bring together the observations of Nagel, and St. Thomas and Aristotle to suggest further conclusions.

Already, from what has been said, it seems that the question of how to bridge the gap between the subjective and objective might be aided by a contribution from our classical visitors, namely, the idea of natures. It is with a view to the Aristotelian-Thomistic view of natures and how we can know them that makes it seem to my mind, that Nagel's hope for a new phenomenology of new concepts will ultimately be frustrated. Nevertheless, using principles that Nagel has put forth in this article together with Thomistic and Aristotelian insights, it is possible to see that this gap, in a way has already been bridged, and in another way, can never be bridged.

In order to address this question I will first discuss Nagel's critique of reductionism and his “speculative proposal” for what a different mode of reductionism might look like. I will attempt to argue that Nagel's hoped for reform must either reduce to the kind of reductionism he critiqued or that it can never be attained. To fully argue this last point I will suggest that what Nagel really wants is what Aristotle and St. Thomas call nature. Consequently, any sort of reductionistic mode of proceeding has, as it were, an infinite distance to traverse. I will then manifest the impediments to knowing natures according to a Thomistic epistemology and how the gap between the objective and subjective is thus crossed and yet not crossed. Having shown the “negative” side of the argument, I will then make a positive argument about what would be necessary according to a Thomistic conception of mind to know natures as Nagel seems to want to. I will suggest that St. Thomas would argue that the kind of knowledge that Nagel is searching for is akin to angelic knowledge. Finally, I will propose a possible exception to the limitations on humanity's inability to bridge the gap between subjective and objective with regard to human persons.





Nagel, Reductionism, and Natures

Nagel's article focuses on consciousness as the phenomena which, as he says, “makes the mind-body problem really intractable.”[3] He points to mental phenomena as the particular aspect of the mind-body problem which is very poorly understood. This leads to what I consider to be the thesis of his paper: “And careful examination will show that no currently available concept of reduction is applicable to [mental phenomena].” [4]

The next paragraph of Nagel's article is very important as it resolves to a common principle. While the tone of the paragraph takes on an hypothetical sense, nevertheless I think that Nagel is appealing to fundamental experience that we cannot soon deny. We will look at this paragraph more carefully below. For now, it is important to point out that Nagel here claims that “conscious experience is a widespread phenomena,” and that “fundamentally an organism has conscious mental states if and only if there is something that it is to be that organism.”[5]

Nagel goes on to describes this as “the subjective character of experience.”[6] Nagel begins to point out that current reductive analyses are not up to the task of accounting for this experience as they are “logically compatible with its absence.” He goes on to say “It is useless to base the defense of materialism on any analysis of mental phenomena that fails to deal explicitly with their subjective character.”[7]

Nagel then makes it very clear that his critique of reductionism is by no means driven by a desire to move away from physicalism, but rather to point out what rigors such a reduction must obtain to account for this, seemingly, undeniable experience. In order to illustrate more fully what he means Nagel turns to bats. He has very good reason for choosing bats to manifest his point. They are sufficiently close to us on the phylogenetic tree and yet their mode of experiencing is very obviously different than our own.[8] A sign of this is that bats depend on echolocation. It is therefore, as Nagel points out, not sufficient for me to imagine what it would be like for me to behave as a bat, he “wants to know what it is like for a bat to be a bat.” [9]

I will let Nagel's own words describe more fully what it is he is looking for:

“We cannot form more than a schematic conception of what it is like [to be a bat]. For example, we may ascribe general types of experience on the basis of the animal’s structure and behavior. Thus we describe bat sonar as a form of three dimensional forward perception; we believe that bats feel some versions of pain, fear, hunger, and lust, and that they have other, more familiar types of perception besides sonar. But we believe that these experiences also have in each case a specific subjective character, which it is beyond our ability to conceive.” [10]



Nagel then briefly touches upon the relation of facts to conceptual schemes. He rightly acknowledges that this is a large topic and he by no means intends to address it fully. He merely points out that, “Whatever may be the status of facts about what it is like to be a human being or a bat, or a Martian, these appear to be facts that embody a particular point of view.”[11] Nor does he hold that this is just a matter of the “alleged privacy of experience to its possessor.” He says that the point of view is a type. It is possible, according to Nagel, to describe the quality of experience of another person.[12] However, he admits that this objective ascription of experience is only possible for someone sufficiently similar to the object of ascription.[13]

The discussion in the article then turns to the dichotomy of a reductionist attempt to grasp subjective experience. Reduction's usual mode is to move away from the subjective to the objective. Precisely what is sought here, however, is the subjective experience. Thus, such a move towards the more objective seems ill suited to the task. Nagel goes so far as to say, “If we acknowledge that a physical theory of mind must account for the subjective character of experience, we must admit that no presently available conception gives us a clue how this could be done.”[14] A little further on Nagel seems to capture the essence of the problem when he says, “Does it make sense, in other words, to ask what my experiences are really like, as opposed to how they appear to me?”[15]

He closes his article with his speculative proposal that was mentioned above, that it may be possible to close the gap between the subjective and the objective. He claims that this can be done if one were to develop an objective phenomenology that is not dependant on empathy or imagination. “Though presumably it would not capture everything, its goal would be to describe, at least in part, the subjective character of experiences in a form comprehensible to beings incapable of having those experiences.”[16]

With all due respect to a very adept thinker, it does seem that Nagel is attempting to hold together that which he just destroyed. His striking critique of reductionism seems to far out weigh the slim hope proposed by this hypothetical new phenomenology. Nagel wants to hold on to physicalism even though he has seemingly silenced it forever. He is right to say that it is a “mistake to conclude that physicalism must be false.” Nothing he has said as dealt it a death blow. He has merely effectively dismissed it as source for ever really explaining what it is to be something. It cannot obtain this. It has nothing to say on the matter. So also, this new phenomenology, on which Nagel pins his rather slim hopes, will either reduce to that which he just critiqued, or is simply impossible.

When Nagel speaks of trying to “develop concepts that could be used to explain to a person blind from birth what it was like to see,”[17] it is as if he is hoping that this new phenomenology will give humanity a new kind of consciousness, the likes of which we cannot grasp in our present condition.

The problem with this view, is that this new consciousness must develop from our current consciousness. What is more, it can only ever be artificial, and at root will have to resolve to the consciousness that is given as a fact of human existence. To put it another way, an attempt to describe the first person experiences of another must always resolve to our necessarily third person descriptions of objective claims. Therefore, it reduces back to the kind of reduction he just dismissed as insufficient for the task. We must be resigned to this undeniable given of our consciousness.

It is here that I wish to turn to our two guests from the 4th century B.C. and 13th century A.D. While I am afraid that I will here neglect Nagel as long as he is holding on to his physicalism, it is not my purpose to disprove such a theory here. I do intend to argue, however, that what Nagel is really seeking is the Aristotelian-Thomistic concept of nature; and while this will not answer all his wants, it will give a cause for the insufficiency of reductionism and offer an explanation for certain limits on well we can know others.

I will here quote in full a paragraph that we briefly referenced in the above summary.

Conscious experience is a widespread phenomenon. It occurs at many levels of animal life, though we cannot be sure of its presence in the simpler organisms, and it is very difficult to say in general what provides evidence of it. (Some extremists have been prepared to deny it even of mammals other than man.) No doubt it occurs in countless forms totally unimaginable to us, on other planets in other solar systems throughout the universe. But no matter how the form may vary, the fact that an organism has conscious experience at all means, basically, that there is something it is like to be that organism. There may be further implications about the form of the experience; there may even (though I doubt it) be implications about the behavior of the organism. But fundamentally an organism has conscious mental states if and only if there is something that it is to be an organism -something it is like for the organism.[18]


In this paragraph Nagel reveals that he wants the “what it is to be” of an organism and to really grasp that with his mind.

Compare this with a claim by Aristotle, “Nature is a certain principle and cause of moving and resting in that in which it is, primarily, in virtue of itself, and not accidentally.”[19] Prima facie, these claims have very little in common. While respecting the obvious differences, let us look more carefully at Aristotle's claim. First of all, this arises in the context of his Physics and here he is studying mobile being. [20]Consequently, his definitions are going to pertain to this end. Notice, however, that he holds that it is in the thing primarily, in virtue of the thing itself, not accidentally. In other words, the nature pertains essentially to the account of what a thing is.

A little further on Aristotle begins to explain analogous uses of the term nature. In particular he identifies nature with the form or species of things. “Whence, in another way, nature would be the form and species of things which have in themselves a principle of motion, [which species is] not separable except according to account. What is from these is not nature, but by nature, e.g. man. And this [form] is more nature than the material.”[21] The form, however, is the actuality or, the what is to be of the thing and this he identifies with nature. We see, therefore, that Aristotle's account of nature is much closer to what Nagel wants than it may have first appeared.

We should note that this use of nature is far different from our common idea of Nature, as in Mother Nature. For Aristotle (and St. Thomas, as we will see below), nature is not some existing force encompassing all non-human creation. Rather it is an intrinsic principle of the thing; the what is to be of something. Consequently, rather than speaking of Nature, we will speak of natures, or a nature.

Here we will turn to St. Thomas in order to see a concise account of the final developments of the use of the word nature.

“[Essence] is also called by another name, nature, by taking nature according to the first way of those four ways which Boethius assigns in De Duabus Naturae, namely, according as everything that is able to be grasped of each thing by the intellect is able to be called nature. For a thing is not intelligible except through its definition and essence.[22]


Thomas says further, “Nevertheless the same name nature taken in this way signifies the essence of the thing according as it has an order towards some proper operation of the thing; since no thing is without its own proper operation.”[23] Therefore we see that the Aristotelian-Thomistic concept of nature is the what it is to be a thing that Nagel wants to possess so thoroughly. However, while acknowledging that we can know these natures in one way, both Aristotle and St. Thomas are quick to point out, at the same time, our inability to understand such natures perfectly. In particular, St. Thomas in his De Veritate, indicates several impediments to knowing the natures of things.

The rest of this paper, therefore, divides into two main parts. The first will be to point out the limits of knowing the natures of others. The second will point out the possible exception to understanding the subjective experiences of others in the case of the human person.

Impediments to Knowing Natures

In order to understand the impediments to knowing natures, it is necessary to give a brief (very brief) outline of a Thomistic epistemology. For St. Thomas, the object of our thought is things. First of all we sense some thing. From this sense impression we form a phantasm which is the likeness of the thing. Finally we abstract the essence of the thing from the phantasm, and thus we know the thing itself. It is important to note here that the essence is an immaterial principle, first of the thing, and then as known by the intellect. Knowing, for the St. Thomas, is the immaterial possession of another as other.

A corollary principle that is derived from this is that to the degree something is immaterial is to the extent it is knowable.

With this brief outline we can then begin to consider the impediments there are to knowing the natures of things. There are seven impediments to knowing natures, and some of these have variations under them. First of all there is the thing itself. A dog, for example, is a composite being, composed of matter and form. To the extent, therefore, that the dog is material, it is not knowable. Therefore, we cannot posses the what it is to be this dog since we cannot possess it wholly as other.

The nature of the thing must be expressed through its sensible accidents.[24] These sensible accidents, therefore, must attempt to express the nature of the thing, even though they may not be able to express the nature fully. Often, no single accident is sufficient to express the nature of the thing. Consequently it requires a number of accidents taken together in order to express the nature.

These accidents are sometimes not adequate to express the nature of the thing. This can either be what is intended by the nature, or by some defect in the nature. In the first case it is clear that some things by nature attempt to deceive as to what their nature is.[25] Take, for example, the insect the walking stick. It is an insect, however, in order to deceive predators, etc., its nature is not adequately expressed by its accidents so that it looks like a twig. As to the second case there are some occasions where the thing is deformed so dramatically that the nature of the thing is only discerned with great difficulty. Such a thing might happen in the case of sever dismemberment.

These are the three impediments to knowing a nature that can arise on the part of the thing itself. There are also, however, impediments in the medium. All sensing must be done through a medium.[26] This medium might not be well suited to transmit the sensible accidents of the thing. For example, trying to see what color a thing is under a black-light, or attempting to hear during a wind storm. In both these instances, the medium is ill suited to transmit the sensible accident of the thing.

This brings us to the sense organs of the thing itself. There are occasions when the sense organ itself is not capable of receiving the sensible accidents of the thing in a way sufficient to grasp the nature of the thing. This deficiency can be in three ways: first, according to nature, second, according to defect and third, according to habituation. An example of the first way is found when the eye by nature can only see so far, or within such a light spectrum. Consequently, for a man, the sensible accidents of a thing that is a mile away might be received in a poor way due to the power of the sense organ, whereas an eagle might be able to perceive it quite clearly. The second way arises when the sense organ is damaged either wholly or partially. The third way is found when we sense something that we are not accustomed to seeing or that we are not accustomed to seeing in a certain way. Here, the habituation of the sense organ might make it unable to adequately receive the sensible accidents of the thing.

Once the sensible accidents have been received it then belongs to the common sense to unite these accidents. The common sense however, can fail either according to defect or according to habituation. Defects in the common sense most often are seen to arise with some sort of brain damage. Habituation of the common sense, similar to habituation of the senses, can cause someone to not observe something because they are not expecting it.

Then a phantasm is formed of the thing. This phantasm is a likeness of the thing but can become abstracted from particular determinations of the thing, such as determinate dimensions. Therefore, while it is certainly a likeness of the thing, and the essence of the thing itself is present in the phantasm, nevertheless, it is present under and through this indeterminate likeness.

The agent intellect abstracts the essence, or nature of the thing, from the phantasm. While the agent intellect does this unerringly, it does not necessarily do it completely. This imperfection can arise on the part of the object, as has been seen, or on the part of the agent intellect itself. When the imperfection is on the part of the object, the agent intellect can only abstract what is clearly present. Thus, if the sensible accidents of a thing are poorly expressed through an improper medium and at a great distance, the intellect might only be able to abstract something like “a being.” It seems possible also, that some agent intellect might be stronger than another, and therefore more apt to abstract the nature of the thing.[27]

Finally the will can effect our knowledge of nature. According to the scholastic dictum, all error lies in the will. That is to say, one might want to know a thing so much that he neglects to be attentive to what he actually knows of the thing and presume to make more determinate statements than is in accord with what is in his intellect. This is not a movement by the intellect, but a movement of the will. This can cause us to cease reflecting on experience because we imagine that we know something that we do not. This in turn will make it so that we do not strive to reflect on our experience more carefully and understand the natures of things better.

At the end, this process seems to be quite perilous to ever knowing a nature. While this must be granted, nevertheless, it will behoove us to see what kind of knowledge we have at the end of this process. This knowledge is not quite so intimate a knowledge as Nagel seems to be wanting. We are still separated from the thing itself. However, we are able to recognize an instance of this nature versus that nature, in most instances. For example, I am not usually puzzled as to whether the thing in front of me is a dog or a cat. I feel quite certain that they each have a different nature. I am prevented, however, from giving a proper definition of each. To be frank, any definition is going to be a description of accidents which to pertain to the nature more directly.

Moreover, there may be cases where I can be confused about the nature of the thing before me.[28] This is clear from the litany of impediments given above. These hard cases should not be the measure. For example, I may be confused about whether a venus fly trap is a plant or an animal, but that does not mean that I do not know what an animal or a plant is, or that I cannot recognize them in most other cases. Again, looking above to all the possible impediments, we should not be surprised to run into difficult cases. Exceptions are not the foundations of knowledge.

This is not at all the same as a reductionist view. The reductionist wants to reduce the 'what it is to be' to such a description and he is justly criticized by Nagel. The Aristotelian-Thomistic position agrees with the reductionist to this point: we might never be able to give a better definition of the thing than to describe its more essential accidents. This is as far as the two positions will go together. The Aristotelian-Thomistic position might be content with such description as what we can say as to the definition of a thing, but it will insist that this is not the, ‘what it is to be’ a thing. We are naming things that flow from the essence of the thing, even if we do not grasp it perfectly. We can recognize natures, give accounts for them, but we cannot fully grasp them.

Therefore, we see that there are seven impediments to knowing the natures of things, some of these necessary; others, possible, and still others, likely. There are three on the part of the thing itself: it is a composite, the nature of the thing is expressed through sensible accidents of the thing, and these can sometimes deceive, either through defect, or intent. On the part of the medium through which the sensible accidents must be sensed it may be unable to adequately carry the sensible accidents to the sense organs. The subject who is desiring to know likewise can cause impediments to knowing the nature of the thing. First on the part of his senses, and second because he must abstract the essence of the thing. Finally, because his will can blind him to his own experience.

Therefore, we see that there is a certain way in which the gap between the subjective and objective is crossed, in that we have the nature as understood is the same as the nature of the thing, essentially. However, since we must know the nature through our senses, the way we grasp the nature of the thing will always be impeded. Nagel's desire to “know what it is like for a bat to be a bat,” appears to be impossible for us to satisfy. To see what it would entail to possess such a knowledge, we must look to intellects that are something more than human.

Angelic Knowledge

The subject matter of this section might be quite distressing for a physicalist, such as Nagel was when he wrote the article we are here considering. Be that as it may, St. Thomas would hold that the kind of knowledge that Nagel is seeking about natures belongs to the angels. Nagel wants to know what it is like for a bat to be a bat; he wants an objective first person view, a perspective inside the very consciousness of a bat. As we saw, a Thomistic epistemology does not give a favorable impression as to the likelihood of ever obtaining such knowledge. Therefore in order to better appreciate the limitations and achievements of human knowing we will set it in contrast to an angelic mode of knowing, as conceived by St. Thomas. What is important about this consideration is not to discuss angels. In fact, one need not even necessarily believe that there are such beings in order to see the three main points of this section: first, that an Arisotelian-Thomistic view of knowing leaves room for different modes of knowing. Second, human knowing is by no means an exemplar. Third, the kind of 'first person' knowledge of the mental events of another is a mode of knowing proper to angels. Thus, even if angels are here considered only hypothetically, nevertheless we can see what it would take to know things as Nagel seems to want to.

Angelic knowledge is possibly the most difficult and most essential part of the study of the angels. The difficulty is trying to understand beings that in a way are like us, and in another way are completely beyond us. In order to get as close as possible to Nagel's first person experiences we want to address how it is that these glorious beings can consider the actions of men. Are they constantly present among us, watching? Or perhaps this is superstitious medieval fancy, and they know us only because they reason to our existence from their own. Both of these accounts are lacking, but hold some element of the truth. As will be shown, angels, according to a Thomistic account know individual human acts through intelligible species handed down to them by God.

We shall proceed by following, for the most part, St. Thomas' own order of treatment of angels as found in his Summa Theologiae. St. Thomas does not have an article which directly pertains to angelic knowledge of human actions. Therefore, as my topic is far narrower than his treatment I will of course skip those articles that are not to my purpose. First we will consider the medium of angelic knowledge. Then, skipping angelic knowledge of immaterial things, we will proceed directly to the knowledge of material things. There will then be a brief discussion of human actions in general and then the argument for the thesis. We will then take a brief moment to dwell on the consequences of the preceding arguments.

A medium of knowledge is the species through which an intellect knows some thing. Now in man, as is seen in Book III of Aristotle's De Anima, knowledge is had through a universal species that is abstracted from a phantasm in the imagination, present there from an object sensed. This cannot be so in angels. Angels are held to be pure intellects, i.e. separated forms that are their own natures.[29] Consequently, the medium for angelic knowledge must be more carefully examined.
That the angel might be distinguished clearly from God, it should be made clear that he does not know all things through his own substance; for the angel possesses a particular substance, and this substance does not contain the perfection of being in itself. As the Angelic Doctor says himself,

However, the essence of the angel does not comprehend in itself all things, since the existence of a essence is determined to some genus and species. But this is proper to the divine essence, that is infinite in itself simply and comprehends the perfections of all things. Therefore, only God knows all things through his essence.[30]

Therefore, it is clear that the angels must know by some other medium, and that their intellects must be perfected by some species in order to know.[31]

Already, from what has been said, we can see that it is not through some abstracted species that an angel knows. As St. Thomas says, “The species through which an angel understands is not taken from things but is con-natural to them.”[32] St. Thomas argues that human souls, since they are united to matter, are perfected through matter, otherwise their union with matter would be in vain. However, angels are not in matter in any way. Therefore, in order for angels to be perfected by some intelligible species, it must come from an intelligible “efflux,” that comes from God directly.[33] This is not surprising insofar as God is the cause of being and perfection of all things.[34] Therefore, God as he is causing things in existence is at the same time informing the angels with the intelligible species of the existing things.

Now, St. Thomas says that the species of things are con-natural to the angels. It is not that the species come from the very nature of the angel, it is that the nature of the angel requires species to obtain its perfection. Note that St. Thomas makes his argument through perfection, but he is not speaking of the supernatural perfection of eternal beatitude, but simply the perfections which belong to a thing. For example, if God were to create a lion and put no other animals on earth, this would be highly unfitting. To eat meat belongs to the nature of the lion. Therefore, it is con-natural to the lion that there be some animal to eat, otherwise the nature is in vain and cannot obtain its natural perfection. So also, the angel must have some intelligible species granted to them by God directly, otherwise they can in no way obtain their natural perfection and their nature is in vain.

It remains then to see how angels are able to know singulars. Necessarily then, we must take under consideration things in matter. St. Thomas argues from the order of things in nature. The superior beings are more perfect than the inferior and contain the perfections of the inferior eminently, wholly and simply. This is as much to say, anything a man can do, an angel can do better. There is a gradation in the order of things. God is the source of all things and all perfections. The angels are nearest to God in the order of being. St. Thomas then says,

Thus, therefore, all material things are in angels, preexisting simply. Indeed and more immaterially than in things themselves; but more multiplied and more imperfect than they exist in God.[35]

St. Thomas then concludes, in the same place, that since God knows material things, then the angels know them by some intelligible species given by God.

It is important to emphasize that, while God is the cause of being of things, and thus it is clear that creatures exist in Him above all things, the angels are not a cause of our being. Their knowledge of us is given to them directly by God, not as though they are necessary agents of His causality,[36] but because in order for these creatures to know it must come from God, not from creatures simply. See how clearly St. Thomas puts it in his reply to the first back in Question 55, Article 2

In the mind of an angel there are similitudes of creatures, not indeed, as taken from the creature, but from God, who is the cause of creatures and in which the first similitudes of things exist. Whence Augustine says in [The Literal Interpretation of Genesis] that just as the ratio by which a creature is fashioned, first is in the Word of God before it is fashioned in the creature, so the same ratio is made first in the intellectual creatures [i.e. the Angels] and then is itself fashioned in the creature.

We can now consider how angels know singulars. St. Thomas begins his discussion of this question by addressing two common errors. The first of which is the outright denial of knowledge of singulars in angels. This is against the Catholic faith, which holds that angels minister to individual humans; these we call guardian angels. Others have stated that angels know singulars through universal causes. St. Thomas shows that this does not end the difficulty, because to know through universal causes is not the same as to know the thing in the here and now. He gives the example of the astronomer knowing through causes that an eclipse is going to happen, but does not know it in its singularity unless he senses it.[37]

St. Thomas again appeals to the superiority of angels to show that they must know singulars if we do, since there is a certain perfection in knowing singulars in the here and now. He therefore argues that God causes all things, not just universally, but in their very individuality; is the cause of each individual substance. Therefore, even the very individual must exist in God preeminently. Socrates, exists in God first and foremost. Thus the angels know Socrates in his very singularity through a species given by God.[38]

Human actions are caused by God's agency through the will. Human actions begin in deliberation. This deliberation is about the means to the final end which belongs to man by nature. The deliberation necessarily results in choice.[39] That choice terminates in action. It is important to realize, in order to avoid the Pelagian error, that God must be the cause of any and all actions because there is in fact some being there. Moreover, that the first movements of deliberation are caused by God's direct action upon the human will There is no human action without God's causing it immediately, just as there is no being of any sort without God's causing it directly.

We are left, therefore, with the question of how angels can know these particular actions of men. Remember above what St. Thomas concludes about angelic knowledge of singulars, that it is precisely the thing its singularity, the here and now, that the angel knows. This follows for all kinds of being caused by God. As was discussed above, God is the immediate cause of being of every action. Therefore, the angel knows individual actions of men as made known to them by God himself, through some intelligible species.
There is an inclination is to say that angels must in some way make the individual actions of man present to himself in some immaterial way, even though it cannot be asserted how it is done. This view supported by considering the way demons are able to judge human thoughts by outward appearances. For as Augustine says demons “sometimes are able with the greatest facility learn man's dispositions, not only through speech, but also as conceived in thought when the soul expresses them by certain signs in the body”[40]. It seems therefore that the angels (and demons) are able to somehow consider man's actions directly. Moreover, to say that the knowledge is from some intelligible species of the individual it seems that one necessarily falls into some form of determinism. Angels would be able to conclude to individual actions from the intelligible forms of individuals. However, as St. Thomas argues, angels are unable to know that secret thoughts of men. For the will is moved by God alone and directly.[41] Therefore angels cannot perceive the principle of human action, so likewise, they cannot conclude to human actions from intelligible forms of individuals. Therefore, it seems that angels must in some way understand the individual human action from the man's action directly and since there is no form to abstract, the angel is not knowing it through abstraction, and thus this does not contradict what was said before.

The source of this difficulty seems to arise from the mode of human knowing. We know particulars directly from the particulars as sensed. This seems to us the most direct and simple way to know things. However, like most things man does, this is backwards. God knows things perfectly since He knows things in the order of being and through the cause of being, i.e. Himself. Angels, even naturally speaking are much more like to God than we are, and also know according to the mode of being. As was shown above, they cannot abstract. There is no agent or passive intellect, nor imagination in which to hold a phantasm.

The solution lies in this: God is the cause of being for every being, even accidental being. Therefore, He is even the cause of the being of actions. Therefore, as He is causing the action to be, sense there is some new ens, qualified though it may be, he reveals this to the angel through an intelligible species. Not that the angel sees this particular action as necessarily resulting from what is to be Socrates, but rather, since there is this particular man Socrates, he must necessarily act in some particular way here and now. The ens Socrates, is the occasion for the ens running, or cutting in Socrates. The angel cannot see into the deliberation of Socrates, but he is able know the action of Socrates as caused by God directly.

This is a mind blowing and staggering conclusion. We can imagine that an angel must be flooded with virtually infinite number of intelligible species as every single creature in the world, and every accidental being belonging to it (list the categories of a given moment) at every moment. However, this not simply the case. St. Thomas shows that an angel cannot understand many things at the same time. For the unity of an operation requires the unity of the object. Angels cannot know all things at once, because they are not infinite. Therefore they are only able to have one object for the operation of their vis intellectiva. To fill this out we can look at St. Thomas' consideration of whether the higher angels understand by fewer species. He argues that since God understands all things through himself in an absolute unity, inferior creatures know through many. Thus, those that are closer to Him know must by so much the fewer species understand all intelligible things. Therefore, his intelligible species are more universal.[42] Angels, therefore are not then attentive to all particulars accept in so far as the fall under the account of the universal species that they are considering.

Let us consider some speculative corollaries of this to help put the magnificence of this mode of knowing into perspective. Some have suggested that the highest angels are able to understand all creatures through the single species, created being. This does not seem unlikely especially considering what Dionysius says about the first hierarchy of angels in Chapter 7 of The Celestial Hierarchy.

They [Seraphim, Cherubim and Thrones] are perfect then not because of an enlightened understanding which enables them to analyze the many sacred things, but rather because of a primary and supreme deification, a transcendent and angelic understanding of God's work. They have been directed hierarchically not through other holy beings but directly from God Himself and they have achieved this thanks to the capacity which compared to others is the mark of their superior order. Hence they are found next to perfect and unfailing purity and are led, as permitted, into contemplation regarding the immaterial and intellectual splendor.

Dionysius is here speaking of the beatified angels, but what is most telling is that he attributes their proximity to God to “the capacity which compared to others is the mark of their superior order.” It is not hard to imagine, then, that the higher angels can take up the entire universe in a single glance; that they are so powerful that the universe itself is able to be a locus of their power. Through the one species, created being, they understand the natures of every created being now in existence. Thus, the spiritual realm is vastly beyond our own meagre material existence.

In light of the above it would behoove us to take a brief look at angelic intelligible species. Intelligible species is not said univocally of man and angels, but analogously. First, consider that every intelligible species we possess carries with it the account of abstracted, and therefore universal. Angels labour under no such deficiency. They do not require that something be made universal in order for it to be understood. They understand it precisely in its particularity. The greatest angels are able to grasp Socrates-ness through the species created being.

We therefore see according to St. Thomas' thought that angels are subsisting intellects. From their nature they must receive intelligible species con-natural to them from God directly and these species are of all created being, even accidental being. Therefore it is through these species handed down by God that they understand human actions in the here and now. In this way, they can have knowledge through the cause of even particular actions. Among particular human actions we can include many of the phenomena proper to consciousness. Angels, therefore, are able to have objective knowledge of even first person experiences.

This conclusion seems to correspond with what Nagel wants in his knowledge of things. Nagel is emphatic that he is not just “adverting here to the alleged privacy of experience to its possessor. The point of view in question is not one accessible only to a single individual. Rather it is a type.”[43] So also the knowledge that angels have of individual human acts cannot violate the “inner sanctum” of human consciousness as St. Thomas points out when he says that angels cannot know the secret thoughts of men. This would seem to keep them from knowing what it is like for Socrates to be a man. However, they are still privy to what it is like for a man to be a man.

A Speculative Proposal

In this section I am going to follow Nagel's lead and offer my own speculative proposal. My own speculative proposal will at first look very much like Nagel's: there may be a way that man is able to more fully bridge the gap between the subjective and objective. I will go further with Nagel and say that its success seems to depend upon the development of a phenomenology. At this point, however our paths diverge. Nagel wants a phenomenology that would still lie in physical considerations. The phenomenology that I would look to is that which may subsist in the relationships between two human persons.

While an Aristotelian-Thomistic epistemology seems to exclude the kind of knowledge that Nagel wants as a possibility for human intellects, nevertheless, it does leave open a possibility that Nagel himself seems to suggest, namely, that knowledge of another's first person experience may be more realizable the more similar it is to ourselves. As was quoted above Nagel holds, “the objective ascription of experience is possible only for someone sufficiently similar to the object of ascription to be able to hold this point of view.” Nagel the goes on to state the principle negatively, “The more different from oneself the other experiencer is, the less success one can expect with [being able to hold the point of view of the other].[44]

It seems to me that an Arisotelian-Thomistic view would allow for such a position, but determine it more. This view holds that every human person has the same nature. That is to say, each instance of a human is likewise a distinct instantiation of human nature, but each instantiation is essentially the same. There is, however, a great deal of difference between each instantiation. This difference is not in the nature, but lies somewhere else.

According to St. Thomas, the principle of individuation is matter. While this is the principle of our individuation, it by no means needs to be considered as the perfection of our individation. We are not merely distinct individuals, we are unique. Now the perfection of the uniqueness of each instance of a human nature, belongs to the personhood of that nature. It is here that we find what St. Thomas holds to be the incommunicable part of our existence.

It seems, therefore, quite possible to imagine that the inter relationship of persons can provide for a more intimate knowledge of the experiences of the other. There is not the impediment of knowing a different nature. It seems possible, therefore, that there may be a chance to bridge the gap between subject and object in a more profound way.

I would be surprised if this entailed finding new concepts and ways of describing color as Nagel seems to want. Rather, the kind of development, as I see it, would develop a kind of empathy between persons. Perhaps philosophy and science will still only be able to describe this kind of knowledge. I can imagine that this kind of empathy will be found to be pre-philosophical. Perhaps this kind of knowing has actually been going on from the beginning, and I am merely reinventing the wheel. For, it was in the beginning that “Adam knew Eve, his wife.”[45]

Conclusion

We began this paper with a summary of Thomas Nagel's article, What is it like to be a bat? In the summary of this article we pointed out his critique of physicalist reductionism, but I attempted to emphasize that what Nagel was really trying to get to was the 'what it is to be' of a bat. It was in his quest for this where he found reductionist theories wanting.

From this we turned to Aristotle and St. Thomas, both of whom held a concept of nature. As we saw, this is not an idea of nature like Mother Nature, or some mysterious presence/force. Rather, it began as “a certain principle and cause of moving and resting in that in which it is, primarily, in virtue of itself, and not accidentally,” and finally developed into “the essence of the thing according as it has an order towards some proper operation of the thing.”

We then had to consider in what mode we understood these natures and consequently examined the seven major impediments to knowing natures. There are three on the part of the thing itself: it is a composite, the nature of the thing is expressed through sensible accidents of the thing, and these can sometimes deceive, either through defect, or intent. On the part of the medium through which the sensible accidents must be sensed it can possibly me unable to adequately carry the sensible accidents to the sense organs. The subject who desires to know likewise can cause impediments to knowing the nature of the thing. First, on the part of his senses; second, because he must abstract the essence of the thing; finally, because his will can blind him to his own experience.

This led us to look at angelic knowledge. For, while the Aristotelian-Thomistic account of human knowing seems to point to something less than what Nagel was seeking, we saw that waht is required for such knowledge is proper to angelic intellects. These immaterial beings are subsisting intellects, and from their nature they must receive intelligible species con-natural to them from God directly. These species are of all created being, even accidental being. Therefore it is through these species handed down by God that they understand human actions in the here and now. In this way, they can have knowledge through the cause of even particular actions. Such knowledge would therefore extend even to certain mental events.

Finally, I made my own speculative proposal, pointing out that since between two human persons there is not a difference in nature, it may be possible to have greater knowledge of another's first person experience, though this knowledge may take on something different than what belongs to philosophical or scientific pursuits.

Therefore, the question of bridging the gap between the subjective and objective is not so neat a problem as we might hope. According to classical thought, Thomas Nagel will have to be content with something less than what he has hoped for in his inquiry into the 'what it is to be of things.' Perhaps also, the sheer ability of the Aristotelian-Thomistic account to explain why we cannot get to the 'what it is to be' of things may be cause enough to consider more carefully their thought.



24



[1] Nagel, Thomas. What is it like to be a Bat? From The Philosophical Review LXXXIII, 4 (October 1974);435-50. I am using the article from a personal source; therefore the page numbers referenced will not correspond to the afore referenced publication.

[2] Cf. Aristotle, De Anima, III, 5.

[3] Nagel, What is it like to be a Bat?, p. 1.

[4] Ibid.

[5] Ibid.

[6] Ibid.

[7] Ibid., p. 2.

[8] Ibid.

[9] Ibid., p. 3.

[10] Ibid.

[11] Ibid., p. 4.

[12] Ibid.

[13] Ibid.

[14] Ibid., p. 6.

[15] Ibid., p. 8.

[16] Ibid.

[17] Ibid.

[18] Ibid., p. 1.

[19] Aristotle. Physics or Natural Hearing: William of Moerbeke Translation Series. Translated and edited by Glen Coughlin. South Bend, IN: St. Augustine’s Press, 2005.

[20] Ibid., I, 2.

[21] Ibid.

[22] Aquinas, Thomas. De Ente et Essentia, Cap. I.: [Essentia] etiam alio nomine natura dicitur accipiendo naturam secundum primum modum illorum quattor, quos Boethius in libro De Duabus Naturae assignat, secundum scilicet quod natura dicitur omne illud quod intellectu quoquo mod capi potest. Non enim res est intelligibilis nisi per diffinitionem et essentiam suam.

[23] Ibid., Tamen nomen naturae hoc modo sumptae videtur significare essentiam rei, secundum quod habet ordinem ad propriam operationem rei, cum nulla res propria operatione destituatur.

[24] Aquinas, Thomas. De Veritate, Q. 1, a. 10, c.

[25] Ibid.

[26] Ibid.

[27] Aquinas, De Veritate, Q. 1, a. 12 c.

[28] Cf. Ibid.

[29] Aquinas, Summa Thologiae, pp. Q.. 50, aa. 1,2,4,.

[30] Ibid., pp Q. 55, a. 1. c. Ipsa autem essential angeli non comprehendit in se omnia, cum sit essential determinate ad genus et ad speciem. Hoc autem proprium est essentiae divinae, qua infinita est, ut in se simpliciter omnia comprehendat perfecte. Et ideo solus Deus cognoscit onia per suam essentiam. Though an interesting question, we will leave aside what is meant by an angel being determined to a genus and species in this paper.

[31] Ibid.

[32] Ibid. a. 2.

[33] Ibid.

[34] Ibid.

[35] Ibid. pp. Q. 57, a. 1: Sic igitur omnia materialia in ipsis angelis praeexistun, simplicius quidem et immaterialius quam in ipsis rebus; multiplicius autem et imperfectus quam in Deo.

[36] This is not to say that God cannot use angels as a mediation for His direct causality, but it is not necessary. Furthermore, it seems that in certain ways God cannot use the angels to cause at all, such as in the case of esse We will avoid this digression.

[37] Ibid. a. 2.

[38] Ibid.

[39] This assuming that the deliberation comes to an end. One might be able to imagine a case where someone is in the grocery store indefinitely, but there is not need to dwell on what is on the least part.

[40] De Divinatione Daemonum as referenced by St. Thomas, Summa Theologiae, pp. Q. 57, a 4.

[41] Ibid.

[42] Ibid., Q. 55, a. 3.

[43] Nagel, What is it like to be a Bat? P. 2.

[44] Ibid. p. 3.

[45] Genesis 4:1.

I have been called upon to give a fellow philosopher who is not familiar with our Stagirite friend a quick run-down on the soul from an Aristotelian perspective. I have to do it in about four minutes, but there will be time for discussion after, and he is especially interested in contrasting it with Plato's view, which he is more familiar with. Obviously with such a short time allowance, the main difficulty here is pedagogical. This is what I've got so far, and I'd appreciate your input:

*** BEGIN PRESENTATION ***
First, there is a methodological point that should govern the whole discussion. As Aristotle argues in the first chapter of the Physics, the proper way to proceed in a science is from confused general notions to more determine ones. This has two ramifications for the study of the soul:

1. The study of the soul, since it concerns a particular kind of body (living bodies), presupposes the general study of nature.
   
2. Within the study of the soul, we should define the soul in general before discussing particular kinds of souls or distinguishing the different powers precisely.

So, beginning the examination of the soul in general, we can say that the first phenomenon in need of explanation is the difference between living and non-living creatures. That there is a difference is obvious and need not be argued; rather, it is the reason there is a science here at all. And since this difference is seen among bodily things, the only things we have experience of, this investigation falls to the natural philosopher.

This phenomena can be further specified: in demarcating some creatures as "living," we are first of all observing various activities, principally local motion and perception. But since a living thing is different than a non-living thing even when it is not engaging its activities, as when it sleeps, what we are looking for is deeper than the activities themselves. In trying to define the soul, therefore, we are chiefly looking for the principle of these activities of life. Since there may be many secondary causes which come together to produce a given action, we can also specify that we are looking for the first principle of the activities of life, the root of all other differences we might point to between the living and non-living.

If you are convinced that there are only three things to be discussed in the nature of a thing (namely: form, matter, and the composite), it is not too hard to see that the soul, or the first principle of the activities of life, is the form. For the principle is not the composite, which is the very thing that needs explaining. Neither can it be the matter. It is true that both matter and form are principles of a thing. We might, for instance say that we are healthy by means of the body as a principle, or by means of health as a principle. But having a body is what the living and non-living have in common, not what makes them differ. The form, however, is that by
which the living thing differs from the non-living and principles the activities of life. And it principles these activities by being act, as opposed to the body, which is a principle by being receptive. So we define the soul as the first act of a living body.
*** END PRESENTATION ***

Given the time constraints, is there anything you would add, take away, or phrase differently?

Below is a first draft of the preface to my thesis. I would appreciate your thoughts and input on it. At this point I feel like it is rather clumsy, and lacks the proper rhetorical flair. Please let me know if anything about it sounds to overbearing, unnecessary, etc.

In the many conversations that I have had concerning this paper I have encountered certain questions and difficulties that this paper presents, and yet are not addressed within the scope of the paper. The questions of which I speak, pertain to the foundations on which this paper, and my own ideas proceed. This foundation can be described (if you will pardon the cliché) as my “world-view,” or as it has elsewhere more aptly been described, my intellectual custom.
By referring to this intellectual custom I do not mean to suggest that I have some wholly unique perspective, nor do I propose to say that different intellectual customs are wholly alienated from one another such that communication is impossible between them (hence I am writing this preface). Rather, I believe that while my perspective, in one sense, is necessarily unique since I am unique. It is likewise necessarily part of a broader community in which I have been formed, raised, and influenced, since it is impossible for us to exist, separated from any outside influence. This broader community is that wherein the intellectual custom I share in exists. (What Aristotle says about arguments)
Judging, therefore, from the sorts of questions I have encountered regarding this paper, I assume that many of those with whom I have conversed come from a somewhat different intellectual custom. Perhaps this means that I am part of some sort of minority, or that I have merely encountered a peculiar sample. Whatever the case may be, I will endeavour to use this preface as an occasion to sketch, as it were, a backdrop for the following paper. This will not be so much argumentative as descriptive, and all this is done with a view to obviating the objections that would not be so much against the thesis as against the approach that is being taken to this thesis.
I want to acknowledge further, that some intellectual custom may be superior to another and that there are somethings that belong to this intellectual custom about which arguments can be made, and about which I can be in error. I wish merely to establish clearly the pertain aspects of the foundation from whence I am proceeding so that questions and objections might be distinguished accordingly.
Chief among my principles is the conviction that Philosophy is about things and attempts to speak of things in so far as they are universal and unchanging. It follows, therefore, that I am more interested in ideas than in those that held the ideas. In this way, the title of this thesis may be somewhat misleading. I am not actually concerned with the thoughts that went through Aristotle or Newton's minds except accidentally. I trust the interpretations of the texts will not be too far from what they think, but nevertheless I must confess that it is possible they would object to the way I portray their thoughts. Nevertheless, this is not a court where persons are being tried, it is a philosophical treatise where ideas are considered, and these ideas are held to be better or worse to the extent they correspond to the way things are. A further consequence that will be noted is how I blithely and liberally use the commentaries of St. Thomas Aquinas to understand Aristotle. I do this because St. Thomas seems to make the best sense of the texts of Aristotle. By makes “the best sense” I mean that he reads them in such a way as they make sense of things and make sense to me. Using the names of Aristotle and Newton, therefore, should be taken as more of a short-hand way of referring to their works.
This chief principle, as I have designated it, presupposes another: that things are intelligible. By many this claim is challenged. If it is not questioned that things can be known at all, there is great debate about to what extent things can be known. As important and interesting as these questions are, they have to be put aside. Unless I am to begin every work with an epistemological treatise, I must take it as given that I am able to know things. (Though how and to what extent merits discussion.)
Another frequent concern that has been brought to my attention is that in comparing Aristotle and Newton I am holding one as better than the other, as if I were pitting them against one another in some intellectual boxing match and that I grant victory to the one I favor. I will here give a glimpse of the following thesis: I will use terms such as “prior” and “more proper.” These are not intended to mean “better,” simply speaking. They will mean better in a certain respect. Prior means that it is better for this one to proceed the other. More proper means that it better suited to this end than the other, and this will be largely due to the other having a different end altogether. In essence, therefore, by saying prior and more proper, I am saying let the first is before that which follows, and that each is better suited to its proper rather than the end of the other.
Having laid down these prefatory remarks, I hope that I have sufficiently established the thought behind my thesis. That philosophy is about things, and that things are intelligible form the cornerstone of my philosophical approach. My clarifications about what it means to be prior and proper are to make clear the rhetorical approach that this thesis intends.

An Inquiry into the Question of Inertia

You will notice that there is much in this article that was taken from my previous post on the definition of motion. I decided to re-direct my ideas and focus on method, more than the actual question of motion and inertia.

St. Thomas Aquinas makes a bold claim concerning Aristotle’s definition of motion saying, “And therefore it is wholly impossible to otherwise define motion through what is prior and more known, but as the philosopher has here defined it.”i Such a claim, from such a mind, warrants a careful look as to the reasons behind a claim of this force. The significance of this inquiry is great. Aristotle's definition of motion is challenged by a fundamental principle of modern day physics, inertia. How to reconcile these ideas or change them is, therefore, an important question for those who do not wish to simply abandon Aristotle and St. Thomas.
We are left then with the quandary of what to do. Modern day thought on the whole encourages us to scorn ancient thought and embrace the current understanding of things. After all, modern science has taken us to the moon. Even so, there is a puzzle. When Aquinas made his bold claim, was he merely stuck in the world of own limited science? Did he make this claim based upon the poor and limited scientific data available at the time? It is interesting to note, that neither he nor Aristotle bring up the importance of accumulating more “data” at all in their explanations. Probably most striking to our modern sensibilities is that neither of them even mentions the idea of force or anything like it in their accounts.
The differences between the present day approach to the physical world and in particular to motion, and the ancient and medieval approach explains many of these difficulties. The modern day physicist proceeds according to what is commonly known as the scientific method. I here define it as a systematic method of inquiry proceeding according to hypothesis and experiment. Consequently, modern scientists establish various models to explain what they experience and then abandon them for another, better model when one should come along.
Aristotle and St. Thomas were engaged in a much different enterprise as can be clearly seen in their works. The classical approach was one that sought, first of all knowledge, or as St. Thomas would have said scientia. This cognate is obviously related to our modern day word for science, but its meaning is much different. Aristotle defines such knowledge in his Posterior Analytics,
“We think we know each [thing] without qualification, but not in the sophistical manner with respect to an attribute, when we think that we know the cause through which the thing exists as being the cause of that thing and that the thing cannot be other than what it is.”ii
As he will later show in his De Anima this knowledge comes from the abstraction of the forms of things by the agent intellect, so that the mind truly knows things.iii
As is clear, the two approaches to understanding the physical world are vastly different. While the differences between these two approaches are such that it seems impossible to say whether one is better than the other, it does seem that we may argue for one being prior to the other. This brings us to the purpose of this paper. While it would be a great task to once and for all settle the question about inertia and the classical definition of motion, at least we can here argue for where we ought to begin looking. My thesis is two-fold: Aristotle's definition of motion is prior to the account of inertia in the order of knowing in that it is self-evident. Consequently, any account of inertia must be able to keep this definition if it is to be taken as true.
To proceed I will first argue that the only valid way to proceed in any inquiry is as Aristotle states in the beginning of the Physics “The natural path is to go from things which are more known and certain towards us toward things which are more certain and more knowable by nature.”iv I will then address some preliminary concerns to the definition of motion. After this, I will examine Aristotle's definition of motion and how he argues that it is true showing that it is in fact self-evident, given Aristotle’s principles of nature. This being shown, I will conclude by claiming that this definition must be held if one is to investigate the physical world, in particular in examining the principle of inertia.

Beginning
In every inquiry in which there are principles or causes or elements, understanding and science occur from knowing these. For we think we know each thing when we know the first causes and first principles and have reached the elements. It is clear, then, that in natural science as well one must try to determine first what concerns the principles.v

So Aristotle opens the physics and directs us to examine the principles of natural philosophy. It is then that he enunciates the principle which will be our primary concern in this essay, “The natural path is to go from the things which are more known and certain to us toward things which are more certain and more knowable by nature.” There are some questions that the formulation of this principle brings up. In particular, the distinction between what is more known to us and what is more known by nature, for this is the principle by which Aristotle justifies this mode of proceeding. In this section I will argue that there is no other way to proceed with certainty and scientia except by this path that Aristotle lays forth. While such an inquiry belongs properly to epistemology, we will be able to touch on this matter briefly.
It is sufficient here to see that there are some things that we are able to see more immediately than others. For instance, I know that the whole is greater than the part, or that equals added to equals are equal. Such axioms are certain and clear to our minds. Further claims, such as the interior angles of a triangle equal two right angles, are true, but certainly cannot be grasped with the immediacy of the afore mentioned axioms. In fact, following Euclid's Elements there are various definitions, axioms and postulates, let alone propositions that I must comprehend before I can see that the interior angles of a triangle are equal to two right angles.vi
The movement in mathematics, however, is simpler than that of Aristotle’s Physics. Aristotle, since he is dealing with physical and therefore sensible realities, must move from his experience of things to the principles, and then from principles to demonstrations. The greater part of the Physics is dedicated to the discussion of principles. It is not until the sixth book (of eight) that Aristotle even begins to do demonstrations, properly so called. Therefore we see that the philosopher of nature must spend time examining his experience, moving from the more known to the less known.
He gives three analogies by which to understand this method. The first: “For the whole is more known according to sensation, and the universal is a certain whole. For the universal embraces many things within it as parts.”vii This analogy allows us to consider our experience in a way like the universal and particular. In our experience of things, say a tree, we realize that this is a kind of whole that is composed of other things which are themselves able to be known. We must be attentive to our experience to see what things might be contained therein.
This idea is further elaborated when Aristotle gives the second analogy, “In a way the same thing happens in the relation of a name to its account. For the name signifies indistinctly some whole, as circle, but the definition of this divides into the single parts.”viii Therefore, given that sensible whole, with its various parts, we see that the whole is grasped by the intellect as something indistinct. To better understand this whole we name and define the parts which are less obvious to us, but simpler and clear ideas in themselves. So in the case of the circle, we see that its principles are the point and the line, and these are more simply intelligible in themselves, but we first know the circle.
Aristotle then gives his final analogy, “And children at first call all men “fathers” and all women “mothers” but later they distinguish each of them.”ix Children take time to distinguish between adult males and adult males with offspring. So also we need time to distinguish those things that look the same to us, so that we must see their differences. As we are defining and seeing parts we will come to distinguish some things that were confused before.
Using these three examples Aristotle establishes that the confused whole that we first grasp, is in fact confused. It is what we know better, but it is not as intelligible on its own as the parts. We must grasp the parts and define and distinguish them in order to understand our experience. We must wade through the various sensations that we have received, and Aristotle gives us an ordered means by which to do so. Start with what we know, and then move forward. To abandon what we knew at first leaves us lost and adrift in the wild ocean of natural philosophy. We see therefore, that the “natural path” is the only path on which we can proceed with certainty. Therefore, it is the only path by which we can proceed scientifically.

Preliminary Considerations
It is well that we should first make a note regarding the most jarring part of my claim about motion that it is self-evident. Something can be self-evident in many ways. There are principles which the mind grasps immediately, and as obvious, such as “the whole is greater than the part.” There are also principles which St. Thomas calls “self-evident to the wise.”x What is characteristic of such principles is that they are not obvious to everyone. However, both kinds share in common that the mind immediately grasps them. What this means is that there is no middle term showing that they are the case, but rather, through sufficient reflection on experience one sees that it is true. This is to say, there is no proper demonstration of the definition of motion.xi (ref.)
It is nonetheless true that Aristotle's definition of motion, “the actuality of what exists in potency, as such,”xii provides challenges. Prima facie, this definition seems incomprehensible. This is because he is defining motion by what is prior to motion. While it seems reasonable enough that we must define motion in terms of something prior to motion, it challenges us, because there does not seem to be motion in the definition. This difficulty can be surmounted, only if we are able to understand how act and potency are prior to motion.
One final note about Aristotle's definition of motion before we proceed: he is not only defining locomotion, that is, motion from place to place. He certainly sees this as the paradigm of motion and will even say that it is at the base of all other kinds of motion, but he will consider growth and diminution, alteration, and locomotion as kinds of motion. Therefore he will speak of motion in very general terms, which is at once an excellence of his account, and a challenge to we who would understand him.
There are certain principles Aristotle assumes that his readers have at this point grasped and understood. I will not here argue to these principles, but take them as given. First of all we should know that there is such a thing as change and what a change is. If one denies that there is change then natural philosophy can have nothing more to say to him. Such an objection is for metaphysics. According to Aristotle, we must understand change to be, generally speaking, the loss or reception of a substantial or accidental form by some substance. Likewise, we must accept that there is such a thing as a nature. Again, the denial of this brings us to metaphysics. Aristotle defines nature as “a certain principle and cause of moving and of resting in that which it is, primarily, in virtue of itself, and not accidentally.”xiii
Aristotle comes to the principles of nature and change and calls these matter, form and privation. These again are taken as given. It is worthwhile here to point out though that these are indeed principles. There is no demonstration that these are true; they are manifested by reflections upon experience. Finally, Aristotle expects us to have some idea of potency and act. While these are likewise principles and therefore indemonstrable, we will pause briefly to see how Aristotle is able to come to the ideas of potency and act.
Aristotle first mentions the ideas of actuality and potentiality as a proper consideration of natural philosophy in Book II chapter 1. Here we are introduced first to potentiality when he says, “We would not yet claim, in the former case, that the bed has anything according to art if it is only a bed potentially and had not yet the species of a bed.”xiv He is here setting up an analogy between nature and art. The timber is potentially a bed just as matter is potentially flesh. This analogy is very similar to the one he uses to show that there is prime matter. There he argues that as the timber is to the bed, so is there some underlying principle that stands to formxv. He thus moves from matter to see that there is potency, a more general idea that something can be something, but is not. The idea of actuality immediately follows as a correlative. Therefore, when the timber is, the bed, it is no longer the bed potentially but actually.

Definition of Motion
When beginning his inquiry into the definition of motion Aristotle lays out those things that are concomitant to motion.xvi This should make us realize that a complete understanding of what motion is, will be impossible until we have considered the continuous, the infinite, place, void, and time. Having given us this context Aristotle makes a division between potency and act. “There is, then, something which is only in actuality and something in potency and actuality.”xvii This is the first of three divisions that he makes in his search for the definition of motion. As Glen Coughlin points out in his appendix on the definition of motion, it is important to note what is meant by potential.xviii He is dividing act from potency and for this division to be helpful, and then there must be things that stand in opposition to one another. For instance, it does not aid our inquiry to say that I have the potency to stand because I am standing. Therefore, we must understand potency together with privation of some act. However, we cannot confuse potency and privation.
Aristotle proceeds to explain the basis for relations as excess and defect, action and passion, the mover and the mobile. He leaves this aside at this time, but he will return to this consideration when discussing the relation between the mover and the moved. We shall also take this up below.
The second distinction is made when Aristotle states, “motion is not beyond things.”xix That is to say, that it is not beyond any of the categories. The final distinction points out that in every genus there is a being and privation of that being.
We see from the first division that motion must belong to what can be in potency and act. This is clear if we consider that motion is a kind of change, which is obvious from experience. What does not have potency (and this is potency understood with privation, as was said) is unable to change, for there is, as it were, nowhere for it to go. Therefore, motion must pertain to what can be in potency and act.
The second distinction, that motion belongs to the categories, must be understood in two ways. First, that motion cannot be some super genus since “one can grasp nothing common.”xx Second, we must understand that motion is not some eleventh category since there is “nothing beyond the things named.”xxi We may therefore conclude from this that motion is going to be understood in the context of a genus.
The third distinction concerning the being and privation in each genus indicates where to look for motion in a genus. That is, it is going to be somewhere between the being and privation, the white and the black or the perfect and imperfect, etc. It must be clear that when Aristotle says that “the species of motion and change are as many as are those of being,”xxii it does not mean that there is motion in every genus, as he will later deny, but he is claiming that as many categories as admit of motion, so many will the species of motion be. There will not be one kind of motion for multiple categories.
From the above we may conclude that motion belongs to those things that are in act and potency in some genus, according to the mode of that genus. We must take this together with our common experience of motion. We know motion as that which is between its two ends, “that from which” and “that towards which.” For we see the apple moving from green to red, or the child growing to his full height when a man, or the cup being here, and then being there. Such is out experience of motion.
What we know about motion at this point is its ends. For I know that the mobile is here or there, but when it is here or there I do not say that it is in motion. Therefore, since we know the ends of motion and we must always proceed from what is more known to the less known, then we must define motion in terms of its ends. For the sake of generality we will names these ends, “that from which” and “that towards which”
The end “from which” is what the mobile posses now, before it has gone somewhere. It is the end that is held in act. The end towards which is what is held in potency, the mobile is not there. We also see that there are any number of points in between these two at which the mobile could be said to be if its motion did not continue on. The mobile has no intrinsic order away or towards either end if it comes to rest at one of these points. If I get up and walk to the doorway and stop, I do not belong to either room more than the other. It is only in motion that I have an order towards or away from some point.xxiii
From these considerations we see that motion is a kind of potency, since it does not possess its end. We see also that there is a kind of actuality to motion. The points at which the motion could stop are closer to the end, so long as we take the order provided by the motion, than the point from which the motion began. Therefore, as long as it is moving it is becoming the end towards which.
Now, the end that towards which is what the mobile holds in potency, before and during the motion. Once the mobile holds the end towards which in act the motion is completed. However, we may still define this in terms of the end from which as the end from which. In order to do this in the language of act and potency, we say that mobile at the end “towards which” is the actuality of the potency. Or in a parallel formulation to Aristotle's definition, it is the actuality of what existed in potency.
So far, we are still speaking of the ends and not of what lies between them. We therefore want to understand the end “towards which” as it exists in potency, not as it existed. Therefore we must understand that potency insofar as it is still in potency. This is our definition: the actuality of what exists in potency, as it is in potency. As Aristotle phrases it, “the actuality of what exists in potency, as such, is motion.”
We see therefore, that Aristotle proceeds by starting with what is prior and more known, namely potency and act. We then consider what is “in between” these and this is what gives us motion. The argument works by the mode of manifestation. If something is in potency it is not moving, and if it is in act it is done moving, we therefore must look to what is between. There is however, no cause of this definition given. We do not see why motion is this way; we see only that it must be this way. This is what is proper to a principle, that there is no cause of it that the mind can grasp; we see only that it is.
Inertia
Sir Isaac Newton first introduced the world to the idea of inertia in his treatise Natural Philosophy’s Mathematical Principles. Right away we see that his conception of natural philosophy is different that Aristotle’s, given that he is searching for its mathematical principles. For Aristotle, mathematics and philosophy of nature were two very different things. We will discuss more of these differences below. In this section I will argue that Newton’s approach to natural philosophy is positivist in nature and that he proceeds as a mathematician.
Newton introduces us to the idea of inertia in the third definition. “Innate force of matter is the power of resisting, by which and body whatever, as much as is in it, perseveres in its state either of resting or of moving uniformly in a directed line.”xxiv By innate force of matter I am understanding inertia. This understanding seems to hold weight given the first sentence of the explanation of his definition, “This force is always proportional to its body, and does not differ in anything from the inactivity {inertia} of the mass except in the mode of conceiving it.”xxv At this point, there is not much to say regarding his method, only that he has proposed definitions of things that may or may not exist and that these definitions bring up questions them.
After his definitions Newton expounds the philosophical framework in which theses definitions are to be understood. In his Scholium Newton explains his understanding of “Time, space, place, and motion.”xxvi There is much that can be questioned in his accounts but to do so would divert us from our purpose. We will here only note what he does.
After his Scholium Newton introduces us to his “axioms or laws of motion.”xxvii The first law is that which interests us, as it is the law of inertia. “Every body perseveres in its state of resting or moving uniformly in a directed line, except insofar as it is compelled to change its state by impressed forces.” immediately there seem to be difficulties. First of all questions arise such as “What does it mean for a body to be in a state of motion?” and “What is force?” These questions should then lead us to wonder what Newton could mean by calling these axioms. This law seems to be a far cry from “The whole is greater than its parts.”
We see that this proceeds very much like Euclid’s Elements. Euclid first lays down his definitions postulates and common notions and then proceeds. There is no discussion of these principles. This seems to be more acceptable since most of these seem fairly straightforward.However, when Newton begins a study of natural philosophy thus, it seems to beg many questions that are not here addressed. What Newton has effectively done is proposed a model by which to understand the phenomena. The certainty that we have in his explanation comes from seeing how effectively it explains the phenomena. This is what has become known as positivism.
In his highly influential work The Structure of Scientific Revolutions, Thomas Kuhn undertakes to describe the process of scientific revolutions and points out that they are essentially changes of what he calls “paradigms”xxviii That is, someone posits another model by which to understand the phenomena and the majority take hold of it. This is essentially what Newton has done. He has put forth a way of understanding the world. This includes the definitions and the Scholium which we mentioned earlier. This world view and the laws by which he describes it are far from axiomatic. This is not to say that they are false, merely that are not immediately grasped by the mind, and that a great amount of discussion should be gone through before accepting these ideas as true. We must work through our experience to see these as principles.
It seems right that Einstein has improved on Newton and his theories have taken precedence.xxix We will not, however, go on to discuss Einstein, because it is beyond our purpose. It is of concern here to put forth the way in which modern empirical science ought to proceed, not to describe how it has proceeded. What is more, I am not here going to criticize the principle of inertia, but only provide certain requirements which adherents to this principle must meet. This is the subject of the final section.
Conclusion
Newton's method fails to proceed according to the natural path as laid down by Aristotle. The language he uses seems to indicate that he is, but on a closer examination, we see that there are significant gaps. The difficulties with Newton's method are that he treats physical objects mathematically and that he does not proceed from what is more known to us, to what is more known by nature. What follows is that his method is not scientific in the classical sense.
The argument about treating physical objects mathematically has hitherto only been implied in this paper. A further discussion of this question would belong to a different study that would examine the various degrees of abstraction, and to what extent certainty can be had in these various degrees and whether there can be any overlap. Since this would take us beyond our primary purpose, we will leave this discussion aside and attend to the second difficulty raised, namely, Newton's invalid mode of proceeding.
Given that Newton is discussing natural philosophy he should proceed in the manner the Aristotle did, moving from the confused whole to principles, and from principles to demonstrations. As we saw above, Newton instead posits his principles, much like the mathematician. The difficulty here is that these principles are not axiomatic as we saw. There needs to be arguments to manifest that these are in fact principles.
There are two ways to go from here, one is to supply the missing dialectic of Newton’s Principia, and try to manifest his principles, or to say that Newton's project is wholly other than that of Aristotle's and that we ought not to hold him to the same standards. It is a different method. Given that Einstein does improve on Newton and effectively throw out Newton's world view, I will take the harder case, that Newton is undertaking a wholly different project.
This position is lent credence by examining the very title of the work, where it speaks of mathematical principles. Throughout his work Newton will express phenomena in a mathematical way. This seems to be vastly different than the way Aristotle speaks of motion and comes to his definition. If this is the case, as it seems that it is, then the question resolves back to the first difficulty raised regarding Newton's method, namely treating physical objects mathematically.
What can be said here is that this may in fact be a valid means of proceeding. The modern scientific hypothetical-deductive method has seemingly accomplished much and we should be loath to abandon it simply because it does not seem to conform so precisely to Aristotle's “natural path.” However, despite the great ability of this method to accomplish things, we must also be wary not to throw out the method of Aristotle. To use contemporary terminology, Aristotle is doing philosophy and Newton is doing science. Aristotle's method provides certainty, while Newton's does not seem to do so. If then we are to proceed effectively and with knowledge, then any account of inertia and inertial motion should be informed by what is held with certainty by following Aristotle. Aristotle's definition of motion is therefore prior in the order of knowing, as it is held with certainty and to further understand inertia and the world about us, we must hold on to what we know and proceed to into the unknown.

NOTES
i Thomas Aquinas In Pysicam bk. 3, lectio 2
ii Aristotle, Posterior Analytics, 1.2.71b10-2
iii Aristotle, De Anima, 2.5.
iv Aristotle Physics 1.1.184a17-19
v Ibid., 184a9-16
vi Euclid, Elements bk.1
vii Aristotle, Physics 1.1.184a25-27
viii Ibid., 184b9-11
ix Ibid., 184b12-13
x Thomas Aquinas, Summa Theologiae, I, Q.1, a1
xi Thomas Aquinas, In Physicam, bk.III, lectio 2
xii Aristotle Physics 3.1.201a11-12
xiii Ibid., 2.1.192b21-23
xiv Ibid., 193a34-36
xv Ibid., 1.7.191a9-11
xvi Ibid., 3.1.200b16-26
xvii Ibid., 200b26-27
xviii Aristotle. Physics Or On Natural Hearing, ed. and trans. Glen Coughlin, William of Moerbeke Translation Series, (South Bend IN :St. Augustine’s Press, 2005), App. 6, 246.
xix Aristotle Physics 3.1.200b33
xx Ibid., 200b34-35
xxi Ibid., 201a3
xxii Ibid., 201a9
xxiii Aristotle. Physics Or On Natural Hearing, ed. and trans. Glen Coughlin, William of Moerbeke Translation Series, (South Bend IN :St. Augustine’s Press, 2005), App. 6, 248.
xxiv Isaac Newton Natural Philosophy’s Mathematical Principles, ed. Chris Decaen, trans Ronald Richard , (Thomas Aquinas College, 1996) 3.
xxv Ibid.
xxvi Ibid., 6.
xxvii Ibid., 11.
xxiii Thomas Kuhn, The Structure of Scientific Revolutions 3rd ed., 10
xxix Antonio Moreno, “The Law of Inertia and the Principle Quidquid Movetur ab Alio Movetur,” Thomist 38 (1974) 313-316.

In the following essay I briefly explicate the definition of motion as given by Aristotle. This is an excerpt from a larger work that has been modified to stand on its own. This will be the first in a series of articles that is concerned with motion. In particular we will discuss inertia and its validity as a principle, especially in light of the definition of motion and the principle, "omnia quod movetur ab alio movetur"

Defining motion poses a daunting task for any thinker. This is for two reasons: First, motion is not very much of a being. As will be shown below, it has only a kind of potential, or imperfect being and this is the the reason that Aristotle notes that “it is difficult to grasp what motion is.”i . Second, it is very much a principle of our coming to understand nature, and as such, it is one of those things that is more known by nature, and less known to us. On account of these difficulties, definitions tend to fail in one of two ways. They end up being circular, such as Descartes' and Newton ii after him, or they end up neglecting the continuity of motion as notably done by Bertrand Russell.iii Aristotle's definition is the only definition that obviate these difficulties and comes to the truth. As St. Thomas says, “It is altogether impossible to define motion through what is prior and more known accept as the philosopher defines it here.”*
It is nonetheless true that Aristotle's definition of motion, “the actuality of what exists in potency, as such,”iv provides its own challenges. Prima facie, this definition seems incomprehensible. Indeed, Descartes remarked famously about this passage, “Who understands theses words?”v In addition to the difficulties that we are confronted with above, Aristotle's definition is hard because he is defining motion by what is prior to motion. While it seems reasonable enough that we must define motion in terms of something prior to motion, it challenges us, because there does not seem to be motion in the definition. This difficulty can be surmounted, only if we are able to understand how act and potency are prior to motion.
One final note about Aristotle's definition of motion before we proceed: he is not only defining locomotion, that is, motion from place to place. He certainly sees this as the paradigm of motion and will even say that it is at the base of all other kinds of motion, but he will consider growth and diminution, alteration, and locomotion as kinds of motion. Therefore he will speak of motion in very general terms, which is at once an excellence of his account, and a challenge to we who would understand him.
When beginning his inquiry into the definition of motion Aristotle lays out those things that “are concomitant to motion.”vi This should make us realize that a complete understanding of what motion is, will be impossible until we have considered the continuous, the infinite, place, void, and time.vii Having given us this context Aristotle makes a division between potency and act. “There is, then, something which is only in actuality and something in potency and actuality.”viii This is the first of three divisions that he makes in his search for the definition of motion. As Glen Coughlin points out in his appendix on the definition of motion, it is important to note what is meant by potential.ix He is dividing act from potency and for this division to be helpful, then there must be things that stand in opposition to one another. For instance, it does not aid our inquiry to say that I have the potency to stand because I am standing.x Therefore, we must understand potency together with privation.
Aristotle proceeds to explain the basis for relations as excess and defect, action and passion, the mover and the mobile.xi He leaves this aside at this time, but he will return to this consideration when discussing the relation between the mover and the moved. We shall also take this up below.
The second division is made when Aristotle states, “motion is not beyond things.”xii That is to say, that it is not beyond any of the categories. The final distinction points out that in every genus there is a being and privation of that being.xiii
We see from the first division that motion must belong to what can be in potency and act. This is clear if we consider that motion is a kind of change, which is obvious from experience. What does not have potency (and this is potency in the sense of privation, as was said) is unable to change, for there is, as it were, no where for it to go. Therefore, motion must pertain to what can be in potency and act.
The second distinction, that motion belongs to the categories must be understood in two ways. First, that motion cannot be some super genus since “one can grasp nothing common.”xiv Second, we must understand that motion is not some eleventh category since there is “nothing beyond the things named.”xv We may therefore conclude from this that motion is going to be understood in the context of a genus.
The third distinction concerning the being and privation in each genus, indicates where to look for motion in a genus. That is, it is going to be somewhere between the being and privation, the white and the black or the perfect and imperfect, etc. It must be clear that when Aristotle says that “the species of motion and change are as many as are those of being,” it does not mean that there is motion in every genus, as he will later deny, but he is claiming that as many categories as admit of motion, so many will the species of motion be. There will not be one kind of motion for multiple categories.
From the above we may conclude that motion belongs to those things that are in act and potency in some genus, according to the mode of that genus. We must take this together with our common experience of motion. We know motion as that which is between its two ends, “that from which” and “that towards which.” For we see the apple moving from green to red, or the child growing to his full height when a man, or the cup being here, and then being there. Such is out experience of motion.
It is worthwhile to point out that to a large extent our current question focuses on this claim precisely, that is, must motion have an end. For now, it is important to see what we experience simply of motion, such as in the examples given. Moreover, even inertial motion must be defined in terms of non-motion. Finally, inertial motion is certainly less known than the above examples and is consequently not profitable to examine at this point. We must proceed from what is more known to what is less known.xvi Therefore we will begin here and see if we need to clarify our definition later.
What we know about motion at this point is its ends. For I know that the mobile is here or there, but when it is here or there I do not say that it is in motion. Therefore, since we know the ends of motion and we must always proceed from what is more known to the less known, then we must define motion in terms of its ends. For the sake of generality we will names these ends, “that from which” and “that towards which”
The end “from which” is what the mobile posses now, before it has gone somewhere. It is the end that is held in act. The end towards which is what is held in potency, the mobile is not there. We also see that there are any number of points in between these two at which the mobile could be said to be if its motion did not continue on. The mobile has no intrinsic order away or towards either end if it comes to rest at one of these points. If I get up and walk to the doorway and stop, I do not belong to either room more than the other. It is only in motion that I have an order towards or away from some point.
From these considerations we see that motion is a kind of potency, since it does not posses its end. We see also that there is a kind of actuality to motion. The points at which the motion could stop, are closer to the end, so long as we take the order provided by the motion, than the point from which the motion began. Therefore, as long as it is moving it is becoming the end towards which.
Now, the end that towards which is what the mobile holds in potency, before and during the motion. Once the mobile holds the end towards which in act the motion is completed. However, we may still define this in terms of the end from which as the end from which. In order to do this in the language of act and potency, we say that mobile at the end “towards which” is the actuality of the potency. Or in a parallel formulation to Aristotle's definition, it is the actuality of what existed in potency.
So far, we are still speaking of the ends and not of what lies between them. We therefore want to understand the end “towards which” as it exists in potency, not as it existed . Therefore we must understand that potency insofar as it is still in potency. This is our definition: the actuality of what exists in potency, as it is in potency. As Aristotle phrases it, “the actuality of what exists in potency, as such, is motion.”xvii
We have therefore defined motion. The definition is good insofar as it is in terms of what is prior and what is more known. Indeed St. Thomas claims that it is wholly impossible to define motion in another way, by what is prior and more known, than as the philosopher defines it here.xvii This does not mean that all of our difficulties are resolved. However, we have perhaps narrowed down what the difficulties are. Aristotle's approach seems reasonable enough and he is certainly proceeding from common experience. Our question then must turn towards inertial motion. We must see how inertial motion influences our definition. The definition can change by expanding, and going beyond what have said, certainly. However, any sort of claim made by inertial motion which contradicts what has been said, should straight away be seen as an error, for this would be to contradict our experience. The other logical possibility is that inertial motion is not motion, but this would be strange. We speak about these things now, in a vague and indistinct way. For now, let what has been said suffice for our present consideration, and we shall take up these further difficulties later.


xviii omnino impossibile est aliter definire motum per priora et notiora, nisi sicut philosophus hic definit. (In Physicam, Lib. III, lectio 2)