A Summary of The Summa Theologiae, I, qq. 15-17, By Thomas Aquinas

A Summary of The Summa Theologiae, I, qq. 15-17, By Thomas Aquinas

In Question 15, Of Ideas, Thomas answers: it is necessary to suppose ideas in the divine mind. Ideas are understood in the forms of things, existing apart from the things themselves. In all things not generated by chance, the form must be the end of any generation whatsoever. As then the world was not made by chance, but by God acting by His intellect, there must exist in the divine mind a form to the likeness of which the world was made. And in this the notion of an idea consists. (P.117) There cannot be an idea of any whole, unless particular ideas are of those parts of which the whole is made. So, then, it must needs be that in the divine mind there are the proper ideas of all things. Hence Augustine says "that each thing was created by God according to the idea proper to it," from which it follows that in the divine mind ideas are many. (P.118) As ideas, according to Plato, are principles of the knowledge of things and of their generation, an idea has this twofold office, as it exists in the mind of God. (P.120)

In Question 16, Of Truth, Aquinas answers that there is this difference between the appetite and the intellect, or any knowledge whatsoever, that knowledge is according as the thing known is in the knower, whilst appetite is according as the desirer tends towards the thing desired. Thus the term of the appetite, namely good, is in the object desirable, and the term of the intellect, namely true, is in the intellect itself. (P.121) Since everything is true according as it has the form proper to its nature, the intellect, in so far as it is knowing, must be true, so far as it has the likeness of the thing known, this being its form, as knowing. For this reason truth is defined by the conformity of intellect and thing; and hence to know this conformity is to know truth. (P.122) God’s being is not only conformed to His intellect, but it is the very act of His intellect; and His act of understanding is the measure and cause of every other being and of every other intellect, and He Himself is His own existence and act of understanding. Whence it follows not only that truth is in Him, but that He is truth itself, and the sovereign and first truth. (P. 125) Although the essences or forms of things are many, yet the truth of the divine intellect is one, in conformity to which all things are said to be true.

In Question 17, Concerning Falsity, Aquinas replies that: in things that depend on God, falseness cannot be found, in so far as they are compared with the divine intellect; since whatever takes place in things proceeds from the ordinance of that intellect, unless perhaps in the case of voluntary agents only, who have it in their power to withdraw themselves from what is so ordained; wherein consists the evil of sin. (P125) Falsity is not to be sought in the senses except as truth is in them. Now truth is not in them in such a way as that the senses know truth, but in so far as they apprehend sensible things truly, and this takes place through the senses apprehending things as they are, and hence it happens that falsity exists in the senses through their apprehending or judging things to be otherwise than they really are. (P. 131) Since falsity of the intellect is concerned essentially only with the composition of the intellect, falsity occurs also accidentally in that operation of the intellect whereby it knows the essence of a thing, in so far as composition of the intellect is mixed up in it. True and false are opposed as contraries, and not, as some have said, as affirmation and negation. Contraries, however, both assert something and determine the subject. A thing is false, as the Philosopher says (Metaph. iv, 27), inasmuch as something is said or seems to be something that it is not, or not to be what it really is. As truth implies an adequate apprehension of a thing, so falsity implies the contrary. Hence it is clear that true and false are contraries. (P.133).