Of Truth

Of Truth — St. Thomas Aquinas asks: Whether truth resides only in the intellect?; Whether truth resides only in the intellect composing and dividing?; Whether the true and being are convertible terms?; Whether good is logically prior to the true?; Whether God is truth?; Whether there is only one truth, according to which all things are true?; Whether created truth is eternal?; Whether truth is immutable?.

Since knowledge is of things that are true, after the consideration of the knowledge of God, we must inquire concerning truth. About this there are eight points of inquiry:

Article 1: Whether truth resides only in the intellect?

The Philosopher says (Metaph. vi), " The true and the false reside not in things, but in the intellect."

As the good denotes that towards which the appetite tends, so the true denotes that towards which the intellect tends. Now 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. Now as good exists in a thing so far as that thing is related to the appetite---and hence the aspect of goodness passes on from the desirable thing to the appetite, in so far as the appetite is called good if its object is good; so, since the true is in the intellect in so far as it is conformed to the object understood, the aspect of the true must needs pass from the intellect to the object understood, so that also the thing understood is said to be true in so far as it has some relation to the intellect. Now a thing understood may be in relation to an intellect either essentially or accidentally. It is related essentially to an intellect on which it depends as regards its essence; but accidentally to an intellect by which it is knowable; even as we may say that a house is related essentially to the intellect of the architect, but accidentally to the intellect upon which it does not depend.

Now we do not judge of a thing by what is in it accidentally, but by what is in it essentially. Hence, everything is said to be true absolutely, in so far as it is related to the intellect from which it depends; and thus it is that artificial things are said to be true a being related to our intellect. For a house is said to be true that expresses the likeness of the form in the architect's mind; and words are said to be true so far as they are the signs of truth in the intellect. In the same way natural things are said to be true in so far as they express the likeness of the species that are in the divine mind. For a stone is called true, which possesses the nature proper to a stone, according to the preconception in the divine intellect. Thus, then, truth resides primarily in the intellect, and secondarily in things according as they are related to the intellect as their principle. Consequently there are various definitions of truth. Augustine says (De Vera Relig. xxxvi), "Truth is that whereby is made manifest that which is;" and Hilary says (De Trin. v) that "Truth makes being clear and evident" and this pertains to truth according as it is in the intellect. As to the truth of things in so far as they are related to the intellect, we have Augustine's definition (De Vera Relig. xxxvi), "Truth is a supreme likeness without any unlikeness to a principle": also Anselm's definition (De Verit. xii), "Truth is rightness, perceptible by the mind alone"; for that is right which is in accordance with the principle; also Avicenna's definition (Metaph. viii, 6), "The truth of each thing is a property of the essence which is immutably attached to it." The definition that "Truth is the equation of thought and thing" is applicable to it under either aspect.

Article 2: Whether truth resides only in the intellect composing and dividing?

the Philosopher says (Metaph. vi) that with regard to simple things and "what a thing is," truth is "found neither in the intellect nor in things."

As stated before, truth resides, in its primary aspect, in the intellect. Now 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. But in no way can sense know this. For although sight has the likeness of a visible thing, yet it does not know the comparison which exists between the thing seen and that which itself apprehends concerning it. But the intellect can know its own conformity with the intelligible thing; yet it does not apprehend it by knowing of a thing "what a thing is." When, however, it judges that a thing corresponds to the form which it apprehends about that thing, then first it knows and expresses truth. This it does by composing and dividing: for in every proposition it either applies to, or removes from the thing signified by the subject, some form signified by the predicate: and this clearly shows that the sense is true of any thing, as is also the intellect, when it knows "what a thing is"; but it does not thereby know or affirm truth. This is in like manner the case with complex or non-complex words. Truth therefore may be in the senses, or in the intellect knowing "what a thing is," as in anything that is true; yet not as the thing known in the knower, which is implied by the word "truth"; for the perfection of the intellect is truth as known. Therefore, properly speaking, truth resides in the intellect composing and dividing; and not in the senses; nor in the intellect knowing "what a thing is."

And thus the Objections given are solved.

Article 3: Whether the true and being are convertible terms?

the Philosopher says (Metaph. ii) that there is the same disposition of things in being and in truth.

As good has the nature of what is desirable, so truth is related to knowledge. Now everything, in as far as it has being, so far is it knowable. Wherefore it is said in De Anima iii that "the soul is in some manner all things," through the senses and the intellect. And therefore, as good is convertible with being, so is the true. But as good adds to being the notion of desirable, so the true adds relation to the intellect.

Article 4: Whether good is logically prior to the true?

What is in more things is prior logically. But the true is in some things wherein good is not, as, for instance, in mathematics. Therefore the true is prior to good.

Although the good and the true are convertible with being, as to suppositum, yet they differ logically. And in this manner the true, speaking absolutely, is prior to good, as appears from two reasons. First, because the true is more closely related to being than is good. For the true regards being itself simply and immediately; while the nature of good follows being in so far as being is in some way perfect; for thus it is desirable. Secondly, it is evident from the fact that knowledge naturally precedes appetite. Hence, since the true regards knowledge, but the good regards the appetite, the true must be prior in idea to the good.

Article 5: Whether God is truth?

Our Lord says, "I am the Way, the Truth, and the Life" (Jn. 14:6).

As said above (), truth is found in the intellect according as it apprehends a thing as it is; and in things according as they have being conformable to an intellect. This is to the greatest degree found in God. For His 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.

Article 6: Whether there is only one truth, according to which all things are true?

it is written (Ps. 11:2), "Truths are decayed from among the children of men."

In one sense truth, whereby all things are true, is one, and in another sense it is not. In proof of which we must consider that when anything is predicated of many things univocally, it is found in each of them according to its proper nature; as animal is found in each species of animal. But when anything is predicated of many things analogically, it is found in only one of them according to its proper nature, and from this one the rest are denominated. So healthiness is predicated of animal, of urine, and of medicine, not that health is only in the animal; but from the health of the animal, medicine is called healthy, in so far as it is the cause of health, and urine is called healthy, in so far as it indicates health. And although health is neither in medicine nor in urine, yet in either there is something whereby the one causes, and the other indicates health. Now we have said () that truth resides primarily in the intellect; and secondarily in things, according as they are related to the divine intellect. If therefore we speak of truth, as it exists in the intellect, according to its proper nature, then are there many truths in many created intellects; and even in one and the same intellect, according to the number of things known. Whence a gloss on Ps. 11:2, "Truths are decayed from among the children of men," says: "As from one man's face many likenesses are reflected in a mirror, so many truths are reflected from the one divine truth." But if we speak of truth as it is in things, then all things are true by one primary truth; to which each one is assimilated according to its own entity. And thus, 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.

Article 7: Whether created truth is eternal?

God alone is eternal, as laid down before ().

The truth of enunciations is no other than the truth of the intellect. For an enunciation resides in the intellect, and in speech. Now according as it is in the intellect it has truth of itself: but according as it is in speech, it is called enunciable truth, according as it signifies some truth of the intellect, not on account of any truth residing in the enunciation, as though in a subject. Thus urine is called healthy, not from any health within it but from the health of an animal which it indicates. In like manner it has been already said that things are called true from the truth of the intellect. Hence, if no intellect were eternal, no truth would be eternal. Now because only the divine intellect is eternal, in it alone truth has eternity. Nor does it follow from this that anything else but God is eternal; since the truth of the divine intellect is God Himself, as shown already ().

Article 8: Whether truth is immutable?

It is written (Ps. 11:2),"Truths are decayed from among the children of men."

Truth, properly speaking, resides only in the intellect, as said before (); but things are called true in virtue of the truth residing in an intellect. Hence the mutability of truth must be regarded from the point of view of the intellect, the truth of which consists in its conformity to the thing understood. Now this conformity may vary in two ways, even as any other likeness, through change in one of the two extremes. Hence in one way truth varies on the part of the intellect, from the fact that a change of opinion occurs about a thing which in itself has not changed, and in another way, when the thing is changed, but not the opinion; and in either way there can be a change from true to false. If, then, there is an intellect wherein there can be no alternation of opinions, and the knowledge of which nothing can escape, in this is immutable truth. Now such is the divine intellect, as is clear from what has been said before (). Hence the truth of the divine intellect is immutable. But the truth of our intellect is mutable; not because it is itself the subject of change, but in so far as our intellect changes from truth to falsity, for thus forms may be called mutable. Whereas the truth of the divine intellect is that according to which natural things are said to be true, and this is altogether immutable.