Lecture 11 — Truth and falsity referred to act

Now, the terms “being” and “non-being” are used in one sense with reference to the categorical figures; in another, with reference to the potency or act of these or their contraries; and in still another sense, they are referred most properly to truth and falsity.

And in things, this consists in being combined or being separated. Hence he who thinks that what is separated is separated and that what is combined is combined is right; but he who thinks about things otherwise than as they are is wrong. And it is necessary to consider what we mean when we say that truth and falsity exist or do not exist. For it is not because we are right in thinking that you are white that you are white, but it is because you are white that in saying this we speak the truth.

Therefore, if some things are always combined and it is impossible for them to be separated, and others are always separated and it is impossible for them to be combined, and others admit of both contraries, then being consists in being combined and being one, and non-being consists in not being combined and being many.

Therefore, with regard to contingent things, the same opinion or statement becomes true and false, and it is possible for it at one time to be true and at another to be false. But with regard to those things that are incapable of being otherwise than as they are, an opinion is not sometimes true and sometimes false, but one is always true and the other always false.

However, with regard to things that are not composite, what is being and non-being, and what is truth and falsity? For such things are not composite so as to exist when combined and not exist when separated—for example, the proposition “the wood is white” or the proposition “the diagonal is incommensurable.”

Nor will truth and falsity still be present in them in the same way as in other things. And just as truth is not the same in these things, in a similar fashion, neither is being the same.

But this is truth or falsity: to come in contact with a thing and to express it is truth (for expression is not the same as affirmation), and not to come in contact with a thing is ignorance. For it is impossible to be deceived about a thing’s quiddity, except in an accidental sense, and the same holds true in the case of incomposite things, for it is impossible to be deceived about them.

And they are all actual and not potential, for otherwise, they would be generated and corrupted. But being itself is neither generated nor corrupted; otherwise, it would be generated out of something.

Therefore, regarding all those things that are really quiddities and acts, it is impossible to be deceived about them, but one must either know them or not. But, concerning them, we may ask what they are, namely, whether they are such and such or not.

Now, considering being in the sense of truth and non-being in the sense of falsity, if one thing is thus composed, then it is true; but if it is not so composed, then it is false.

And if a thing is truly a being, it is thus; but if it is not so, it does not exist at all.

Again, truth means to know these beings, and there is neither falsity nor deception about them, but only ignorance; but not ignorance such as blindness is, for blindness is as if one did not have intellective power at all.

And concerning immobile things, it is also evident that there is no deception about them as regards time, if one assumes that they are immobile.

For example, if one assumes that a triangle does not change, he will not be of the opinion that at one time its angles are equal to two right angles and that at another time they are not; for otherwise, it would change.

But he might assume that one thing has such and such a property and that another has not. For example, one might assume that no even number is a prime number, or that some are and some are not.

But this is impossible as regards one single number, for one will not assume that one thing is such and another is not; but whether he speaks truly or falsely, a thing is always disposed in the same way.

1895. Here the Philosopher compares act to potency with reference to truth and falsity; and in regard to this, he does three things.

First, he claims that truth and falsity are chiefly referred to act.

Second (1051b2; [1896]), he explains what he aims to do, at and in things.

Third (1052a4; [1917]), he draws a corollary, at and concerning.

He accordingly first says that, since being and non-being (which is its opposite) are divided in two ways—first, into the different categories of substance, quantity, quality, and so forth, and second, into the potency and act of one or the other of contraries (since either one of two contraries may be actual or potential)—it follows that true and false are most properly predicated of what is actual.

Truth and falsehood

1896. And in things (1051b2). He now proves his thesis, and in regard to this, he does three things.

First, he makes this clear in the case of continuous substances;

Second (1051b17; [1901]), in that of simple substances, at however, with regard.

Third (1051b33; [1914]), he summarizes both of these, at now, considering.

In regard to the first, he does two things.

First, he explains his thesis, saying that, in things, this (that is, being true or false) consists in being combined or being separated. Hence one who thinks that to be separated which is separated in reality has a true opinion—for example, one who thinks that man is not an ass. And the same is true of one who thinks that to be combined which is combined in reality—for example, one who thinks that man is an animal. But, on the other hand, one who relates things in thought in a way different from that in which they are in their own proper nature has an erroneous opinion—for example, one who thinks that man is an ass, or that he is not an animal—because, when a thing is or is not, it is then said to be true or false.

1897. This must be understood as follows. You are not white because we think truly that you are white; but rather, conversely, we think you are white because you are white. Hence it has been shown that the way which a thing is disposed is the cause of truth both in thought and in speech.

1898. He adds this in order to clarify what he said above, namely, that, in things, truth and falsity consist in being combined and being separated. For the truth and falsity found in speech and in thought must be traced to a thing’s disposition as their cause. Now, when the intellect makes a combination, it receives two concepts, one of which is related to the other as a form. Hence it takes one as being present in the other, because predicates are taken formally. Therefore, if such an operation of the intellect should be traced to a thing as its cause, then in composite substances, the combination of matter and form, or also the combination of subject and accident, must serve as the foundation and cause of the truth in the combination which the intellect makes in itself and expresses in words. For example, when I say, “Socrates is a man,” the truth of this enunciation is caused by combining the form of humanity with the individual matter by which Socrates is this man. When I say, “A man is white,” the cause of the truth of this enunciation is the combining of whiteness with the subject. It is similar in other cases. And the same thing is evident in the case of separation.

1899. Therefore, if some things (1051b9). Second, he concludes from what has been said that, if the combining and separating of a thing is the cause of the truth and falsity in thought and in speech, the difference between truth and falsity in thought and in speech must be based on the difference between the combining and separating of what exists in reality.

Now, in reality, such difference is found to involve combination and separation, because some things are always combined and it is impossible for them to be separated. For example, sentient nature is always united to the rational soul, and it is impossible for the latter to be separated from the former in such a way that the rational soul may exist without the power of sensation, although on the other hand, a sentient soul can exist without reason. Again, some things are separated and it is impossible for them to be combined—such as black and white, and the form of an ass and that of a man. Again, some things are open to contraries, because they can be combined and separated, as man and white and also running.

1900. However, the being in which the intellect’s act of combining consists indicates a certain composition and union inasmuch as there is affirmation. But non-being, which negation signifies, does away with composition and union and indicates plurality and otherness.

Hence it was shown that, in the case of things that may be combined and separated, one and the same statement is sometimes true and sometimes false. For example, the statement, “Socrates is sitting,” is true when he is sitting, but false when he gets up. And the same holds true in the case of thought. But, with regard to those things that cannot be otherwise than they are—that is, those which are always combined or separated—it is impossible for the same thought or statement to be sometimes true and sometimes false; but what is true is always true, and what is false is always false. For example, the proposition, “Man is an animal,” is true, but the proposition, “Man is an ass,” is false.

1901. However, with regard (1051b17). He now explains how truth and falsity can be present in simple things, and in regard to this, he does three things.

First, he shows that truth is not present in the same way in simple things as in composite ones. He says that, with regard to things that are not composite and simple, such as immaterial substances, truth or falsity is not present in them as a result of any combination or separation which occurs in reality, but arises because their quiddity is known or not known. For when we acquire knowledge of the quiddity of any simple being, the intellect seems to be true; and when we fail to acquire knowledge of its quiddity, but attribute something else to it, the intellect is then false.

1902. For there is no composition in simple beings as a consequence of which it could be said that, when the thing is combined, the intellect is then true in making the combination; or that, when that is separated in reality which the intellect combines, the intellect is then not true.

Or to express this in a different way, there is no composition in simple things by reason of which its composition is signified when we express affirmatively that it is so, and of which the separation is signified when we express negatively that it is not so—as happens in the case of composite things: when it is said that a piece of wood is white, its composition is signified, or when it is said that it is not white, or that the diagonal is not commensurable, its separation is signified.

1903. Thus it is evident that truth and falsity are not present in simple things in the same way as in composite things. Nor is this surprising, since being also is not the same in both, but the being of composite things results from their components, whereas that of simple things does not. Now, truth follows being, because the structure of things in being and in truth is the same, as was said in book 2 [298] of this work. Hence those things that are not similar in being are not similar in truth.

1904. But this is truth or falsity (1051b23). Second, he shows how truth and falsity are present in simple things. He says that, in the case of simple things, truth and falsity are such as will be explained; for to come in contact with a simple thing through the intellect in such a way as to apprehend what it is and to express it, that is, to signify this simple thing by a word, is truth present in simple things. And since sometimes the word “to express” is taken for affirmative predication, which involves composition, he rejects this interpretation. He says that affirmation and expression are not the same, because affirmation occurs when one thing is predicated of something else, and this implies combination, whereas expression is the simple utterance of something.

1905. Therefore, to come in contact with simple things through the intellect and to express them constitutes truth, but not to come in contact with them is not to know them at all. For whoever does not grasp the quiddity of a simple thing is completely ignorant of it, because one cannot both know and not know something about it, since it is not composite.

1906. Moreover, since he had said that to come in contact with simple things is to express their truth, it would seem that not to come in contact with them is to be false or in error. He did not say this, however, but said that not to come in contact with a thing is ignorance. Hence he gives the reason why not to come in contact with them is not to be in error about them, saying that it is possible to be in error about their quiddity only accidentally. This must be understood as follows.

1907. It was said above in book 7 [1362] and in book 8 [1710] that, in the case of simple substances, the thing itself and its quiddity are one and the same. Hence, since a simple substance is its own quiddity, the judgment about the knowledge of a simple substance and the judgment about the knowledge of its quiddity are one and the same.

But the intellect is deceived about a quiddity only accidentally; for either a person comes in contact with a thing’s quiddity through his intellect, and then he truly knows what that thing is, or he does not come in contact with it, and then he does not know what it is. Hence, with regard to such a thing, the intellect is neither true nor false. This is why Aristotle says in On the Soul 3 that, just as a sense is always true with regard to its proper object, in a similar fashion, the intellect is always true with regard to its proper object—quiddity. And the fact that the intellect is not deceived about a thing’s quiddity applies not only in the case of simple substances but also in that of composite ones.

1908. Now, it is necessary to consider how one may be accidentally deceived about a quiddity. For a person is deceived about a quiddity only as a result of combining or separating; and with regard to composite substances, this may occur in two ways.

First, it may occur by combining a definition with something defined or by separating them. For example, if someone were to say that an ass is a mortal rational animal, or that a man is not a mortal rational animal, both would be false.

Second, insofar as a definition is composed of parts which are incompatible with each other, as if someone were to give this definition, “Man is a non-sensible animal.” Thus, a definition is said to be false in the first way because it is not the definition of this thing; in the second way, it is said to be false in itself, as the Philosopher has instructed us above in book 5 [1132].

1909. Now, we can be deceived accidentally about the quiddity of simple substances only in the first way, for their quiddity is not composed of many parts in the combining and separating of which falsity can arise.

1910. And they are (1051b28). He adapts his remarks about simple substances to his main thesis, in which he shows that truth involves act rather than potency. Indeed, he had shown this to be true in the case of composite substances insofar as their truth embodies combination and separation, which designate act. But he shows that this is true in the case of simple substances from the fact that they do not contain falsity, but only truth. And for this reason, they are not potential but actual.

1911. He accordingly says that all simple substances are actual beings and are never potential ones; for if they were sometimes actual and sometimes potential, they would be generated and corrupted. But this cannot be the case, as has been shown above [1715], for substances of this kind are forms alone, and for this reason they are also beings of themselves. Now what exists of itself is neither generated nor corrupted, for everything that is generated is generated from something. But being in an absolute sense cannot be generated from anything; for there is nothing apart from being, but only apart from some particular being, just as there is some being apart from man. Hence this being can be generated in a qualified sense, but being in an absolute sense cannot. Hence what is a being of itself cannot be generated, because it is a form, from which being naturally follows. Hence it is not sometimes potential and sometimes actual.

1912. Therefore, since truth consists chiefly in act, it is unfitting that there should be error or falsity in all those things that are actual only and are what something truly is, since they are quiddities or forms; but they must either be understood, if they are grasped by the intellect, or not be understood at all, if they are not grasped by the intellect.

1913. But even though it is impossible to be deceived about these things as regards their essence, this is nevertheless possible when we may ask what they are, that is, whether they are of such and such a nature or not. Hence, it is possible to be deceived about them accidentally, as someone might ask whether a simple substance is fire or a bodily substance or not, because, if it is held to be a bodily substance, there will be falsity accidentally as a result of combination.

1914. Now, considering (1051b33). He summarizes the statements he has made about truth and falsity, with reference both to composite things and to simple ones. He says that this being, which signifies truth, and non-being, which signifies falsity—for he who says that a man is white signifies this to be true, and he who says that a man is not white signifies this to be false—being and non-being in this sense, I say, are used in one way in the case of the composition of things. That is, there is truth if what the intellect combines is combined in reality, but there is falsity if what the intellect combines when it understands or forms a proposition is not combined in reality.

1915. And truth exists in a different way in the case of simple things, if a thing is truly a being, that is, the quiddity or substance of a simple thing, is as it is understood to be. But if it is not as it is understood to be, no truth exists in the intellect. Thus truth consists in understanding these things, but concerning them, there is neither falsity nor error in the intellect, as has been explained [1912], but ignorance; for if one does not grasp the quiddity of a thing, one does not know that thing in any way at all. In the case of composite things, however, one can know one of their properties and be deceived about the others.

1916. Furthermore, he shows what sort of ignorance this is when he says that this ignorance is not a privation such as blindness, which is the privation of the power of sight. Hence that ignorance would be similar to blindness if one did not have the intellective power of acquiring knowledge of simple substances. And from this, it is evident that, according to the opinion of Aristotle, the human intellect can acquire an understanding of simple substances. This is a point which he seems to have left unsolved in On the Soul 3.

1917. And concerning (1052a4). Here he introduces a corollary. He says that it is evident from what has been said that there is no error about immobile things as regards time. But, in the case of contingent things, which are not always so, it is possible to be in error about them as regards time.

For example, if Socrates is going to sit down and someone were to judge this to be so, he could be deceived insofar as he might judge that Socrates is going to sit down when he is not. The same thing would be true if someone were to think that an eclipse will occur when it will not. But, in the case of immobile things and those which always are, the above can occur only in one way, that is, if someone were to think that these things are mobile and that they do not always exist. For he is then in error about them, but he would not be in error as regards time. Hence he says that, if someone thinks that they are immobile, he will not be deceived about them as regards time.

1918. He says this, then, because, if someone assumes that they are immobile, he will not think that they sometimes are and sometimes are not, and thus he is not deceived about them as regards time. For example, if someone thinks that a triangle is unchangeable, he will not be of the opinion that the sum of its angles will sometimes equal two right angles and sometimes will not, for it would then be both changeable and unchangeable.

1919. But, in the case of immobile things, it is possible to consider under one common aspect one thing that has such and such a property and another that has not. For example, it is possible to understand that, under triangle, some triangles are equilateral and others are not. And it is possible to ask whether no even number is prime, or whether some are and some are not—a prime number being one which the unit alone measures. Hence, among even numbers, only the number two is a prime number, but none of the others.

And regarding what is numerically one, in the case of immobile things, it is impossible to be in error or to be deceived even in this. For in the case of something numerically one, it is impossible for anyone to think that one individual can be so and another not be so, for what is numerically one is not divided into many. Hence he will have to say what is true or false in an unqualified sense, since what is numerically one always exists in the same way and is incapable of being diversified in point either of time or of subjects. From this it is clear that truth has to do with act, for immobile things as such are always actual.