It’s been a recurring problem that I don’t have a precise concept of forgiveness. First, I’ll try to lay out a few ground rules about the method for finding a definition.

I will attempt to understand a precise definition using the three sources of philosophy¹:

1. common conceptions, manifested by the way we speak. These will not only be a pre-philosophical source of the precise conception sought, but also the measure of whatever conclusion is reached.
   


2. reason, which can first of all abstract the common conceptions, then can proceed from them, which are more known to us, to a precise conception, which is more knowable by nature.
   


3. prior thinkers, who have taught us not only by their true insights, but even more so by their mistakes.
   

To these three, I’ll throw in another element: Revelation, as guarded by the Magisterium, and explained by the Doctors of the Church. Although this will, hopefully, be a philosophical inquiry, not theological, I think knowledge of God’s forgiveness is rather limited to the philosopher. Revelation, therefore, will provide a welcome check against the universality of the definition, especially considering the impact such a definition will have on the interpretation of Scripture.

Following Aristotle's requirements for a definition, I will seek a universal definition of forgiveness, i.e. one that applies per se to every species of forgiveness, because it contains the middle term, or cause of a demonstrative conclusion. In this way, the definition can explain all the effects and consequences of forgiveness (or at least "facilitate even a conjecture about them"²).
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1. Taken from Charles De Koninck, Three Sources of Philosophy, 1964 Proceedings of the American Catholic Philosophical Association.
2. De Anima, Bk. I, Ch. 1