Selection from St. Thomas Aquinas | M. C. D'Arcy, S.J.

(Westminster, MD: The Newman Press, 1954), 103-104.

St. Thomas was the heir of many worshippers at the shrine of the good--Plato, St. Augustine, and the pseudo-Dionysius--but his own statements are tempered by his preference for the intellect over the will, and as usual he starts with Aristotle: 'The good is that which all things desire.' He apologizes for this vague definition, and at the same time determines its meaning by pointing out that in knowledge we have often to learn of a cause by its effect, though the cause is, in reality, prior to the effect, and should, therefore, in knowledge precede it So, too, in this case, when we call the good the desirable, we do not mean that a thing is good because it is desirable, bu that it is desirable because it is good. That is to say, there is something in objects which makes us want them, and this character it is which goes by the name of the good. Hence, just as being in relation to the mind is the true, so in relation to the appetite it is the good. The good as conterminous with being will have diverse meanings and be only analogously one; and again, that which possesses being completely will be at the same time most desirable, most perfect, and most actual. God is the summum bonum, possessor and possessed in one act; all that is desirable he has and is in an infinite degree. Being in want of nothing, he has fruition of himself and desires nothing out of selfishness. If he diffuses good (bonum est diffusivum sui) then that good redounds to the credit of finite being and makes for finite excellence; it cannot add anything to what is already personified goodness.

Below God there is finite being and with potency there is want, and want is only another word for desire. Now the object desired cannot be wanted save as perfecting or completing in some way the subject of the desire. Therefore a closer analysis of the good reveals it as that which perfects the appetite or the being with the appetite. One step further; every being strives to be itself, to reach, in a metaphysical language, its act. It is defined by its nature to be a certain sort of thing. An engine, for instance, has a certain function, and it is a good engine according as it is capable of performing that function. Our body, again, has its laws which we neglect at our peril. That is to say, that our good is to be what we ought to be, to 'realize ourselves.' Good, then, is another name for perfection, and we can only desire things in so far as they seem in some way to possess what will be for our good. This holds true not only of ourselves but of every being, and it is worthy pointing out that just as potency has a place within being because of its association with act, so too that lack of completion which makes itself felt in desire is positive and good, by reason of the end to which it is directed.