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.
Reply Obj. 1: The soul does not judge of things according to any kind of truth, but according to the primary truth, inasmuch as it is reflected in the soul, as in a mirror, by reason of the first principles of the understanding. It follows, therefore, that the primary truth is greater than the soul. And yet, even created truth, which resides in our intellect, is greater than the soul, not simply, but in a certain degree, in so far as it is its perfection; even as science may be said to be greater than the soul. Yet it is true that nothing subsisting is greater than the rational soul, except God.
Reply Obj. 2: The saying of Anselm is correct in so far as things are said to be true by their relation to the divine intellect.
Whether Created Truth Is Eternal?
Objection 1: It seems that created truth is eternal. For Augustine says (De Lib. Arbit. ii, 8) "Nothing is more eternal than the nature of a circle, and that two added to three make five." But the truth of these is a created truth. Therefore created truth is eternal.
Obj. 2: Further, that which is always, is eternal. But universals are always and everywhere; therefore they are eternal. So therefore is truth, which is the most universal.
Obj. 3: Further, it was always true that what is true in the present was to be in the future. But as the truth of a proposition regarding the present is a created truth, so is that of a proposition regarding the future. Therefore some created truth is eternal.
Obj. 4: Further, all that is without beginning and end is eternal.
But the truth of enunciables is without beginning and end; for if their truth had a beginning, since it was not before, it was true that truth was not, and true, of course, by reason of truth; so that truth was before it began to be. Similarly, if it be asserted that truth has an end, it follows that it is after it has ceased to be, for it will still be true that truth is not. Therefore truth is eternal.
_On the contrary,_ God alone is eternal, as laid down before (Q. 10, Art. 3).
_I answer that,_ 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 (A. 5).
Reply Obj. 1: The nature of a circle, and the fact that two and three make five, have eternity in the mind of God.
Reply Obj. 2: That something is always and everywhere, can be understood in two ways. In one way, as having in itself the power of extension to all time and to all places, as it belongs to God to be everywhere and always. In the other way as not having in itself determination to any place or time, as primary matter is said to be one, not because it has one form, but by the absence of all distinguishing form. In this manner all universals are said to be everywhere and always, in so far as universals are independent of place and time. It does not, however, follow from this that they are eternal, except in an intellect, if one exists that is eternal.
Reply Obj. 3: That which now is, was future, before it (actually) was; because it was in its cause that it would be. Hence, if the cause were removed, that thing's coming to be was not future. But the first cause is alone eternal. Hence it does not follow that it was always true that what now is would be, except in so far as its future being was in the sempiternal cause; and God alone is such a cause.
Reply Obj. 4: Because our intellect is not eternal, neither is the truth of enunciable propositions which are formed by us, eternal, but it had a beginning in time. Now before such truth existed, it was not true to say that such a truth did exist, except by reason of the divine intellect, wherein alone truth is eternal. But it is true now to say that that truth did not then exist: and this is true only by reason of the truth that is now in our intellect; and not by reason of any truth in the things. For this is truth concerning not-being; and not-being has not truth of itself, but only so far as our intellect apprehends it. Hence it is true to say that truth did not exist, in so far as we apprehend its not-being as preceding its being.
Whether Truth Is Immutable?
Objection 1: It seems that truth is immutable. For Augustine says (De Lib. Arbit. ii, 12), that "Truth and mind do not rank as equals, otherwise truth would be mutable, as the mind is."
Obj. 2: Further, what remains after every change is immutable; as primary matter is unbegotten and incorruptible, since it remains after all generation and corruption. But truth remains after all change; for after every change it is true to say that a thing is, or is not.
Therefore truth is immutable.
Obj. 3: Further, if the truth of an enunciation changes, it changes mostly with the changing of the thing. But it does not thus change.
For truth, according to Anselm (De Verit. viii), "is a certain rightness" in so far as a thing answers to that which is in the divine mind concerning it. But this proposition that "Socrates sits", receives from the divine mind the signification that Socrates does sit; and it has the same signification even though he does not sit.
Therefore the truth of the proposition in no way changes.
Obj. 4: Further, where there is the same cause, there is the same effect. But the same thing is the cause of the truth of the three propositions, "Socrates sits, will sit, sat." Therefore the truth of each is the same. But one or other of these must be the true one.
Therefore the truth of these propositions remains immutable; and for the same reason that of any other.
_On the contrary,_ It is written (Ps. 11:2), "Truths are decayed from among the children of men."
_I answer that,_ Truth, properly speaking, resides only in the intellect, as said before (A. 1); 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 (Q. 14, A. 15). 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.
Reply Obj. 1: Augustine is speaking of divine truth.
Reply Obj. 2: The true and being are convertible terms. Hence just as being is not generated nor corrupted of itself, but accidentally, in so far as this being or that is corrupted or generated, as is said in _Phys._ i, so does truth change, not so as that no truth remains, but because that truth does not remain which was before.
Reply Obj. 3: A proposition not only has truth, as other things are said to have it, in so far, that is, as they correspond to that which is the design of the divine intellect concerning them; but it is said to have truth in a special way, in so far as it indicates the truth of the intellect, which consists in the conformity of the intellect with a thing. When this disappears, the truth of an opinion changes, and consequently the truth of the proposition. So therefore this proposition, "Socrates sits," is true, as long as he is sitting, both with the truth of the thing, in so far as the expression is significative, and with the truth of signification, in so far as it signifies a true opinion. When Socrates rises, the first truth remains, but the second is changed.
Reply Obj. 4: The sitting of Socrates, which is the cause of the truth of the proposition, "Socrates sits," has not the same meaning when Socrates sits, after he sits, and before he sits. Hence the truth which results, varies, and is variously signified by these propositions concerning present, past, or future. Thus it does not follow, though one of the three propositions is true, that the same truth remains invariable.
QUESTION 17 CONCERNING FALSITY (In Four Articles) 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.
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."
Obj. 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.
Obj. 3: Further, the true is said to exist in things by conformity to the divine intellect, as stated above (Q. 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" (John 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 Reply Obj. 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.
Reply Obj. 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.
Reply Obj. 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.
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.
Obj. 2: Further, the Philosopher says (Metaph. iv, 24) that falsity is not proper to the senses, but to the imagination.
Obj. 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 (Q. 16, A. 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 Obj. 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.
Reply Obj. 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.
Reply Obj. 3: This argument proves that the false is not in the sense, as in that which knows the true and the false.
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.
Obj. 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 (A. 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 (Q. 16, A. 2), that falsity can exist in the intellect not only because the knowledge of the intellect is false, but 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 (A. 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 Obj. 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.
Reply Obj. 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.
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.
Obj. 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.
Obj. 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" (Jer. 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 Obj. 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."
Reply Obj. 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.
Reply Obj. 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.
QUESTION 18 THE LIFE OF GOD (In Four Articles) 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?
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.
Obj. 2: Further, plants are said to live, inasmuch as they have 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.
Obj. 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 Obj. 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.
Reply Obj. 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.
Reply Obj. 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.
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.
Obj. 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.
Obj. 3: Further, to know God is an operation. But this is life, as is clear from the words of John 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 (Q. 17, A. 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 (Q. 13, A. 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 Obj. 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,