Summa Th. I EN Qu.16 a.8


We next consider falsity. About this four points of inquiry arise:

(1) Whether falsity exists in things?

(2) Whether it exists in the sense?

(3) Whether it exists in the intellect?

(4) Concerning the opposition of the true and the false.

Article: 1 Whether falsity exists in things?

Objection: 1. It appears that falsity does not exist in things. For Augustine says (Soliloq. ii, 8), "If the true is that which is, it will be concluded that the false exists nowhere; whatever reason may appear to the contrary."

2. Further, false is derived from "fallere" [to deceive]. But things do not deceive; for, as Augustine says (De Vera Relig. 33), they show nothing but their own species. Therefore the false is not found in things.

3. Further, the true is said to exist in things by conformity to the divine intellect, as stated above (Question [16]). But everything, in so far as it exists, imitates God. Therefore everything is true without admixture of falsity; and thus nothing is false.

On the contrary Augustine says (De Vera Relig. 34): "Every body is a true body and a false unity: for it imitates unity without being unity." But everything imitates the divine unity yet falls short of it. Therefore in all things falsity exists.

I answer that Since true and false are opposed, and since opposites stand in relation to the same thing, we must needs seek falsity, where primarily we find truth; that is to say, in the intellect. Now, in things, neither truth nor falsity exists, except in relation to the intellect. And since every thing is denominated simply by what belongs to it "per se," but is denominated relatively by what belongs to it accidentally; a thing indeed may be called false simply when compared with the intellect on which it depends, and to which it is compared "per se" but may be called false relatively as directed to another intellect, to which it is compared accidentally. Now natural things depend on the divine intellect, as artificial things on the human. Wherefore artificial things are said to be false simply and in themselves, in so far as they fall short of the form of the art; whence a craftsman is said to produce a false work, if it falls short of the proper operation of his art.

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. Thus sins themselves are called untruths and lies in the Scriptures, according to the words of the text, "Why do you love vanity, and seek after lying?" (Ps 4,3): as on the other hand virtuous deeds are called the "truth of life" as being obedient to the order of the divine intellect. Thus it is said, "He that doth truth, cometh to the light" (Jn 3,21).

But in relation to our intellect, natural things which are compared thereto accidentally, can be called false; not simply, but relatively; and that in two ways. In one way according to the thing signified, and thus a thing is said to be false as being signified or represented by word or thought that is false. In this respect anything can be said to be false as regards any quality not possessed by it; as if we should say that a diameter is a false commensurable thing, as the Philosopher says (Metaph. v, 34). So, too, Augustine says (Soliloq. ii, 10): "The true tragedian is a false Hector": even as, on the contrary, anything can be called true, in regard to that which is becoming to it. In another way a thing can be called false, by way of cause---and thus a thing is said to be false that naturally begets a false opinion. And whereas it is innate in us to judge things by external appearances, since our knowledge takes its rise from sense, which principally and naturally deals with external accidents, therefore those external accidents, which resemble things other than themselves, are said to be false with respect to those things; thus gall is falsely honey; and tin, false gold. Regarding this, Augustine says (Soliloq. ii, 6): "We call those things false that appear to our apprehension like the true:" and the Philosopher says (Metaph. v, 34): "Things are called false that are naturally apt to appear such as they are not, or what they are not." In this way a man is called false as delighting in false opinions or words, and not because he can invent them; for in this way many wise and learned persons might be called false, as stated in Metaph. v, 34.

Reply to Objection: 1. A thing compared with the intellect is said to be true in respect to what it is; and false in respect to what it is not. Hence, "The true tragedian is a false Hector," as stated in Soliloq. ii, 6. As, therefore, in things that are is found a certain non-being, so in things that are is found a degree of falseness.

2. Things do not deceive by their own nature, but by accident. For they give occasion to falsity, by the likeness they bear to things which they actually are not.

3. Things are said to be false, not as compared with the divine intellect, in which case they would be false simply, but as compared with our intellect; and thus they are false only relatively.

To the argument which is urged on the contrary, likeness or defective representation does not involve the idea of falsity except in so far as it gives occasion to false opinion. Hence a thing is not always said to be false, because it resembles another thing; but only when the resemblance is such as naturally to produce a false opinion, not in any one case, but in the majority of instances.

Article: 2 Whether there is falsity in the senses?

Objection: 1. It seems that falsity is not in the senses. For Augustine says (De Vera Relig. 33): "If all the bodily senses report as they are affected, I do not know what more we can require from them." Thus it seems that we are not deceived by the senses; and therefore that falsity is not in them.

2. Further, the Philosopher says (Metaph. iv, 24) that falsity is not proper to the senses, but to the imagination.

3. Further, in non-complex things there is neither true nor false, but in complex things only. But affirmation and negation do not belong to the senses. Therefore in the senses there is no falsity.

On the contrary Augustine says (Soliloq. ii, 6), "It appears that the senses entrap us into error by their deceptive similitudes."

I answer that 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, as said above (Question [16], Article [2]), 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.

The knowledge of things by the senses is in proportion to the existence of their likeness in the senses; and the likeness of a thing can exist in the senses in three ways. In the first way, primarily and of its own nature, as in sight there is the likeness of colors, and of other sensible objects proper to it. Secondly, of its own nature, though not primarily; as in sight there is the likeness of shape, size, and of other sensible objects common to more than one sense. Thirdly, neither primarily nor of its own nature, but accidentally, as in sight, there is the likeness of a man, not as man, but in so far as it is accidental to the colored object to be a man.

Sense, then, has no false knowledge about its proper objects, except accidentally and rarely, and then, because of the unsound organ it does not receive the sensible form rightly; just as other passive subjects because of their indisposition receive defectively the impressions of the agent. Hence, for instance, it happens that on account of an unhealthy tongue sweet seems bitter to a sick person. But as to common objects of sense, and accidental objects, even a rightly disposed sense may have a false judgment, because it is referred to them not directly, but accidentally, or as a consequence of being directed to other things.

Reply to Objection: 1. The affection of sense is its sensation itself. Hence, from the fact that sense reports as it is affected, it follows that we are not deceived in the judgment by which we judge that we experience sensation. Since, however, sense is sometimes affected erroneously of that object, it follows that it sometimes reports erroneously of that object; and thus we are deceived by sense about the object, but not about the fact of sensation.

2. Falsity is said not to be proper to sense, since sense is not deceived as to its proper object. Hence in another translation it is said more plainly, "Sense, about its proper object, is never false." Falsity is attributed to the imagination, as it represents the likeness of something even in its absence. Hence, when anyone perceives the likeness of a thing as if it were the thing itself, falsity results from such an apprehension; and for this reason the Philosopher says (Metaph. v, 34) that shadows, pictures, and dreams are said to be false inasmuch as they convey the likeness of things that are not present in substance.

3. This argument proves that the false is not in the sense, as in that which knows the true and the false.

Article: 3 Whether falsity is in the intellect?

Objection: 1. It seems that falsity is not in the intellect. For Augustine says (Qq. lxxxiii, 32), "Everyone who is deceived, understands not that in which he is deceived." But falsity is said to exist in any knowledge in so far as we are deceived therein. Therefore falsity does not exist in the intellect.

2. Further, the Philosopher says (De Anima iii, 51) that the intellect is always right. Therefore there is no falsity in the intellect.

On the contrary It is said in De Anima iii, 21,[22] that "where there is composition of objects understood, there is truth and falsehood." But such composition is in the intellect. Therefore truth and falsehood exist in the intellect.

I answer that Just as a thing has being by its proper form, so the knowing faculty has knowledge by the likeness of the thing known. Hence, as natural things cannot fall short of the being that belongs to them by their form, but may fall short of accidental or consequent qualities, even as a man may fail to possess two feet, but not fail to be a man; so the faculty of knowing cannot fail in knowledge of the thing with the likeness of which it is informed; but may fail with regard to something consequent upon that form, or accidental thereto. For it has been said (Article [2]) that sight is not deceived in its proper sensible, but about common sensibles that are consequent to that object; or about accidental objects of sense. Now as the sense is directly informed by the likeness of its proper object, so is the intellect by the likeness of the essence of a thing. Hence the intellect is not deceived about the essence of a thing, as neither the sense about its proper object. But in affirming and denying, the intellect may be deceived, by attributing to the thing of which it understands the essence, something which is not consequent upon it, or is opposed to it. For the intellect is in the same position as regards judging of such things, as sense is as to judging of common, or accidental, sensible objects. There is, however, this difference, as before mentioned regarding truth (Question [16], Article [2]), that falsity can exist in the intellect not only because the intellect is conscious of that knowledge, as it is conscious of truth; whereas in sense falsity does not exist as known, as stated above (Article [2]).

But because 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. This can take place in two ways. In one way, by the intellect applying to one thing the definition proper to another; as that of a circle to a man. Wherefore the definition of one thing is false of another. In another way, by composing a definition of parts which are mutually exclusive. For thus the definition is not only false of the thing, but false in itself. A definition such as " a reasonable four-footed animal" would be of this kind, and the intellect false in making it; for such a statement as "some reasonable animals are four-footed" is false in itself. For this reason the intellect cannot be false in its knowledge of simple essences; but it is either true, or it understands nothing at all.

Reply to Objection: 1. Because the essence of a thing is the proper object of the intellect, we are properly said to understand a thing when we reduce it to its essence, and judge of it thereby; as takes place in demonstrations, in which there is no falsity. In this sense Augustine's words must be understood, "that he who is deceived, understands not that wherein he is deceived;" and not in the sense that no one is ever deceived in any operation of the intellect.

2. The intellect is always right as regards first principles; since it is not deceived about them for the same reason that it is not deceived about what a thing is. For self-known principles are such as are known as soon as the terms are understood, from the fact that the predicate is contained in the definition of the subject.

Article: 4 Whether true and false are contraries?

Objection: 1. It seems that true and false are not contraries. For true and false are opposed, as that which is to that which is not; for "truth," as Augustine says (Soliloq. ii, 5), "is that which is." But that which is and that which is not are not opposed as contraries. Therefore true and false are not contrary things.

2. Further, one of two contraries is not in the other. But falsity is in truth, because, as Augustine says, (Soliloq. ii, 10), "A tragedian would not be a false Hector, if he were not a true tragedian." Therefore true and false are not contraries.

3. Further, in God there is no contrariety, for "nothing is contrary to the Divine Substance," as Augustine says (De Civ. Dei xii, 2). But falsity is opposed to God, for an idol is called in Scripture a lie, "They have laid hold on lying" (Jr 8,5), that is to say, "an idol," as a gloss says. Therefore false and true are not contraries.

On the contrary The Philosopher says (Peri Herm. ii), that a false opinion is contrary to a true one.

I answer that True and false are opposed as contraries, and not, as some have said, as affirmation and negation. In proof of which it must be considered that negation neither asserts anything nor determines any subject, and can therefore be said of being as of not-being, for instance not-seeing or not-sitting. But privation asserts nothing, whereas it determines its subject, for it is "negation in a subject," as stated in Metaph. iv, 4: v. 27; for blindness is not said except of one whose nature it is to see. Contraries, however, both assert something and determine the subject, for blackness is a species of color. Falsity asserts something, for 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. For as truth implies an adequate apprehension of a thing, so falsity implies the contrary. Hence it is clear that true and false are contraries.

Reply to Objection: 1. What is in things is the truth of the thing; but what is apprehended, is the truth of the intellect, wherein truth primarily resides. Hence the false is that which is not as apprehended. To apprehend being, and not-being, implies contrariety; for, as the Philosopher proves (Peri Herm. ii), the contrary of this statement "God is good," is, "God is not good."

2. Falsity is not founded in the truth which is contrary to it, just as evil is not founded in the good which is contrary to it, but in that which is its proper subject. This happens in either, because true and good are universals, and convertible with being. Hence, as every privation is founded in a subject, that is a being, so every evil is founded in some good, and every falsity in some truth.

3. Because contraries, and opposites by way of privation, are by nature about one and the same thing, therefore there is nothing contrary to God, considered in Himself, either with respect to His goodness or His truth, for in His intellect there can be nothing false. But in our apprehension of Him contraries exist, for the false opinion concerning Him is contrary to the true. So idols are called lies, opposed to the divine truth, inasmuch as the false opinion concerning them is contrary to the true opinion of the divine unity.


Since to understand belongs to living beings, after considering the divine knowledge and intellect, we must consider the divine life. About this, four points of inquiry arise:

(1) To whom does it belong to live?

(2) What is life?

(3) Whether life is properly attributed to God?

(4) Whether all things in God are life?

Article: 1 Whether to live belongs to all natural things?

Objection: 1. It seems that to live belongs to all natural things. For the Philosopher says (Phys. viii, 1) that "Movement is like a kind of life possessed by all things existing in nature." But all natural things participate in movement. Therefore all natural things partake of life.

2. Further, plants are said to live, inasmuch as they in themselves a principle of movement of growth and decay. But local movement is naturally more perfect than, and prior to, movement of growth and decay, as the Philosopher shows (Phys. viii, 56,57). Since then, all natural bodies have in themselves some principle of local movement, it seems that all natural bodies live.

3. Further, amongst natural bodies the elements are the less perfect. Yet life is attributed to them, for we speak of "living waters." Much more, therefore, have other natural bodies life.

On the contrary Dionysius says (Div. Nom. vi, 1) that "The last echo of life is heard in the plants," whereby it is inferred that their life is life in its lowest degree. But inanimate bodies are inferior to plants. Therefore they have not life.

I answer that We can gather to what things life belongs, and to what it does not, from such things as manifestly possess life. Now life manifestly belongs to animals, for it said in De Vegetab. i [*De Plantis i, 1] that in animals life is manifest. We must, therefore, distinguish living from lifeless things, by comparing them to that by reason of which animals are said to live: and this it is in which life is manifested first and remains last. We say then that an animal begins to live when it begins to move of itself: and as long as such movement appears in it, so long as it is considered to be alive. When it no longer has any movement of itself, but is only moved by another power, then its life is said to fail, and the animal to be dead. Whereby it is clear that those things are properly called living that move themselves by some kind of movement, whether it be movement properly so called, as the act of an imperfect being, i.e. of a thing in potentiality, is called movement; or movement in a more general sense, as when said of the act of a perfect thing, as understanding and feeling are called movement. Accordingly all things are said to be alive that determine themselves to movement or operation of any kind: whereas those things that cannot by their nature do so, cannot be called living, unless by a similitude.

Reply to Objection: 1. These words of the Philosopher may be understood either of the first movement, namely, that of the celestial bodies, or of the movement in its general sense. In either way is movement called the life, as it were, of natural bodies, speaking by a similitude, and not attributing it to them as their property. The movement of the heavens is in the universe of corporeal natures as the movement of the heart, whereby life is preserved, is in animals. Similarly also every natural movement in respect to natural things has a certain similitude to the operations of life. Hence, if the whole corporeal universe were one animal, so that its movement came from an "intrinsic moving force," as some in fact have held, in that case movement would really be the life of all natural bodies.

2. To bodies, whether heavy or light, movement does not belong, except in so far as they are displaced from their natural conditions, and are out of their proper place; for when they are in the place that is proper and natural to them, then they are at rest. Plants and other living things move with vital movement, in accordance with the disposition of their nature, but not by approaching thereto, or by receding from it, for in so far as they recede from such movement, so far do they recede from their natural disposition. Heavy and light bodies are moved by an extrinsic force, either generating them and giving them form, or removing obstacles from their way. They do not therefore move themselves, as do living bodies.

3. Waters are called living that have a continuous current: for standing waters, that are not connected with a continually flowing source, are called dead, as in cisterns and ponds. This is merely a similitude, inasmuch as the movement they are seen to possess makes them look as if they were alive. Yet this is not life in them in its real sense, since this movement of theirs is not from themselves but from the cause that generates them. The same is the case with the movement of other heavy and light bodies.

Article: 2 Whether life is an operation?

Objection: 1. It seems that life is an operation. For nothing is divided except into parts of the same genus. But life is divided by certain operations, as is clear from the Philosopher (De Anima ii, 13), who distinguishes four kinds of life, namely, nourishment, sensation, local movement and understanding. Therefore life is an operation.

2. Further, the active life is said to be different from the contemplative. But the contemplative is only distinguished from the active by certain operations. Therefore life is an operation.

3. Further, to know God is an operation. But this is life, as is clear from the words of Jn 18,3, "Now this is eternal life, that they may know Thee, the only true God." Therefore life is an operation.

On the contrary The Philosopher says (De Anima ii, 37), "In living things, to live is to be."

I answer that As is clear from what has been said (Question [17], Article [3]), our intellect, which takes cognizance of the essence of a thing as its proper object, gains knowledge from sense, of which the proper objects are external accidents. Hence from external appearances we come to the knowledge of the essence of things. And because we name a thing in accordance with our knowledge of it, as is clear from what has already been said (Question [13], Article [1]), so from external properties names are often imposed to signify essences. Hence such names are sometimes taken strictly to denote the essence itself, the signification of which is their principal object; but sometimes, and less strictly, to denote the properties by reason of which they are imposed. And so we see that the word "body" is used to denote a genus of substances from the fact of their possessing three dimensions: and is sometimes taken to denote the dimensions themselves; in which sense body is said to be a species of quantity. The same must be said of life. The name is given from a certain external appearance, namely, self-movement, yet not precisely to signify this, but rather a substance to which self-movement and the application of itself to any kind of operation, belong naturally. To live, accordingly, is nothing else than to exist in this or that nature; and life signifies this, though in the abstract, just as the word "running" denotes "to run" in the abstract.

Hence "living" is not an accidental but an essential predicate. Sometimes, however, life is used less properly for the operations from which its name is taken, and thus the Philosopher says (Ethic. ix, 9) that to live is principally to sense or to understand.

Reply to Objection: 1. The Philosopher here takes "to live" to mean an operation of life. Or it would be better to say that sensation and intelligence and the like, are sometimes taken for the operations, sometimes for the existence itself of the operator. For he says (Ethic. ix, 9) that to live is to sense or to understand---in other words, to have a nature capable of sensation or understanding. Thus, then, he distinguishes life by the four operations mentioned. For in this lower world there are four kinds of living things. It is the nature of some to be capable of nothing more than taking nourishment, and, as a consequence, of growing and generating. Others are able, in addition, to sense, as we see in the case of shellfish and other animals without movement. Others have the further power of moving from place to place, as perfect animals, such as quadrupeds, and birds, and so on. Others, as man, have the still higher faculty of understanding.

2. By vital operations are meant those whose principles are within the operator, and in virtue of which the operator produces such operations of itself. It happens that there exist in men not merely such natural principles of certain operations as are their natural powers, but something over and above these, such as habits inclining them like a second nature to particular kinds of operations, so that the operations become sources of pleasure. Thus, as by a similitude, any kind of work in which a man takes delight, so that his bent is towards it, his time spent in it, and his whole life ordered with a view to it, is said to be the life of that man. Hence some are said to lead to life of self-indulgence, others a life of virtue. In this way the contemplative life is distinguished from the active, and thus to know God is said to be life eternal.

Wherefore the Reply to the Third Objection is clear.

Article: 3 Whether life is properly attributed to God?

Objection: 1. It seems that life is not properly attributed to God. For things are said to live inasmuch as they move themselves, as previously stated (Article [2]). But movement does not belong to God. Neither therefore does life.

2. Further, in all living things we must needs suppose some principle of life. Hence it is said by the Philosopher (De Anima ii, 4) that "the soul is the cause and principle of the living body." But God has no principle. Therefore life cannot be attributed to Him.

3. Further, the principle of life in the living things that exist among us is the vegetative soul. But this exists only in corporeal things. Therefore life cannot be attributed to incorporeal things.

On the contrary It is said (Ps 83,3): "My heart and my flesh have rejoiced in the living God."

I answer that Life is in the highest degree properly in God. In proof of which it must be considered that since a thing is said to live in so far as it operates of itself and not as moved by another, the more perfectly this power is found in anything, the more perfect is the life of that thing. In things that move and are moved, a threefold order is found. In the first place, the end moves the agent: and the principal agent is that which acts through its form, and sometimes it does so through some instrument that acts by virtue not of its own form, but of the principal agent, and does no more than execute the action. Accordingly there are things that move themselves, not in respect of any form or end naturally inherent in them, but only in respect of the executing of the movement; the form by which they act, and the end of the action being alike determined for them by their nature. Of this kind are plants, which move themselves according to their inherent nature, with regard only to executing the movements of growth and decay.

Other things have self-movement in a higher degree, that is, not only with regard to executing the movement, but even as regards to the form, the principle of movement, which form they acquire of themselves. Of this kind are animals, in which the principle of movement is not a naturally implanted form; but one received through sense. Hence the more perfect is their sense, the more perfect is their power of self-movement. Such as have only the sense of touch, as shellfish, move only with the motion of expansion and contraction; and thus their movement hardly exceeds that of plants. Whereas such as have the sensitive power in perfection, so as to recognize not only connection and touch, but also objects apart from themselves, can move themselves to a distance by progressive movement. Yet although animals of the latter kind receive through sense the form that is the principle of their movement, nevertheless they cannot of themselves propose to themselves the end of their operation, or movement; for this has been implanted in them by nature; and by natural instinct they are moved to any action through the form apprehended by sense. Hence such animals as move themselves in respect to an end they themselves propose are superior to these. This can only be done by reason and intellect; whose province it is to know the proportion between the end and the means to that end, and duly coordinate them. Hence a more perfect degree of life is that of intelligible beings; for their power of self-movement is more perfect. This is shown by the fact that in one and the same man the intellectual faculty moves the sensitive powers; and these by their command move the organs of movement. Thus in the arts we see that the art of using a ship, i.e. the art of navigation, rules the art of ship-designing; and this in its turn rules the art that is only concerned with preparing the material for the ship.

But although our intellect moves itself to some things, yet others are supplied by nature, as are first principles, which it cannot doubt; and the last end, which it cannot but will. Hence, although with respect to some things it moves itself, yet with regard to other things it must be moved by another. Wherefore that being whose act of understanding is its very nature, and which, in what it naturally possesses, is not determined by another, must have life in the most perfect degree. Such is God; and hence in Him principally is life. From this the Philosopher concludes (Metaph. xii, 51), after showing God to be intelligent, that God has life most perfect and eternal, since His intellect is most perfect and always in act.

Reply to Objection: 1. As stated in Metaph. ix, 16, action is twofold. Actions of one kind pass out to external matter, as to heat or to cut; whilst actions of the other kind remain in the agent, as to understand, to sense and to will. The difference between them is this, that the former action is the perfection not of the agent that moves, but of the thing moved; whereas the latter action is the perfection of the agent. Hence, because movement is an act of the thing in movement, the latter action, in so far as it is the act of the operator, is called its movement, by this similitude, that as movement is an act of the thing moved, so an act of this kind is the act of the agent, although movement is an act of the imperfect, that is, of what is in potentiality; while this kind of act is an act of the perfect, that is to say, of what is in act as stated in De Anima iii, 28. In the sense, therefore, in which understanding is movement, that which understands itself is said to move itself. It is in this sense that Plato also taught that God moves Himself; not in the sense in which movement is an act of the imperfect.

2. As God is His own very existence and understanding, so is He His own life; and therefore He so lives that He has not principle of life.

3. Life in this lower world is bestowed on a corruptible nature, that needs generation to preserve the species, and nourishment to preserve the individual. For this reason life is not found here below apart from a vegetative soul: but this does not hold good with incorruptible natures.

Summa Th. I EN Qu.16 a.8