ARTICLE III

ARE THOSE THINGS POSSIBLE TO GOD WHICH ARE IMPOSSIBLE TO NATURE?

THE third point of inquiry is whether God can do what nature cannot: and the reply seemingly should be in the negative.

             1. The (ordinary) gloss on Romans xi, 24 says that since God is the author of nature he cannot do what is contrary to nature. Now things that nature cannot do are contrary to nature. Therefore God cannot do them.

             2. As all that is necessary in nature can be demonstrated, so whatsoever is impossible in nature can be disproved by demonstration. Now every conclusion of a demonstration involves the principles of that demonstration: and all principles of demonstration imply the principle that yes and no cannot be both true at the same time. Therefore this principle is involved whenever a thing is impossible to nature. But according to the respondent God cannot make yes or no to be both true at the same time. Therefore he cannot do what is naturally impossible.

             3. There are two principles under God, reason and nature. Now God cannot do what is impossible to reason, for instance, that a genus be not predicated of its species. Neither therefore can he do what is impossible to nature.

             4. As false and true are in relation to knowledge, so are possible and impossible to operation. Now God cannot know what is false in nature; therefore he cannot do what is impossible in nature.

             5. So far as there is uniformity among a number of things, what is proved of one is taken to be proved of all: thus if it be proved of one triangle that the three angles equal two right angles, we take this to be proved of all triangles. Now all impossible things apparently agree in the point of their being possible or impossible to God: both in relation to the doer, since God's power is infinite, and in relation to the thing done, since everything has an obediential potentiality to God. Therefore, if there be anything naturally impossible that God cannot do, seemingly he cannot do anything that is impossible.

             6. It is written (2 Tim. ii, 13) that God is faithful, he cannot deny himself. But he would deny himself, says the (interlinear) gloss, if he fulfilled not his promise. Now, as God's promise comes from God, so is all truth from God: because (according to a gloss of Ambrose on I Corinthians xii, 3, No man can say, the Lord Jesus, but by the Holy Ghost) all truth, by whomsoever uttered, is from the Holy Ghost. Therefore God cannot act counter to the truth. He would, however, were he to do what is impossible. Therefore he cannot do what is naturally impossible.

             7. Anselm says (Cur Deus homo, i, 24) that God cannot do what is in the least way unbecoming. Now it would be unbecoming for yes and no to be true at the same time, because the mind would be in a fix. Therefore God cannot do this; and consequently he cannot do whatever is impossible to nature.

             8. No artist can work counter to his art, since this is the very principle of his work. But God would be working against his art, were he to do what is impossible in nature, because the order of nature, in relation to which that thing is impossible, is a reflection of the divine art. Therefore God cannot do what is naturally impossible.

             9. That which is impossible in itself is more impossible than what is impossible accidentally. Now God cannot do what is accidentally impossible, for instance, that what has been should not have been; thus Jerome says (Ep. 22, Ad Eustoch., de cust. virg.) that God, whereas he can do other things, cannot make a virgin of one who is not a virgin. See also Augustine (Contra Faust. xxvi, 5) and the Philosopher (Ethic. vi, 2). Therefore God cannot do what is in itself naturally impossible.

             1. On the contrary, it is written (Luke i, 37): No word shall be impossible with God.

             2. Any power that can do one thing, but not another, is limited. If, then, God can do what is possible to nature, but not that which is impossible, or some that are impossible and not others, it would seem that his is a limited power, which is contrary to what we have proved above. Therefore, etc.

             3. That which is uncircumscribed by anything in existence, cannot be hindered by anything in existence. Now God is uncircumscribed by anything in existence. Therefore nothing in existence can be a hindrance to him: so that the truth of the principle of contradiction cannot be a hindrance to God's action. The same applies to all other principles.

             4. Privation is not susceptive of degrees. Now the impossible connotes privation of power. Therefore if God can do one impossible thing, for instance restore sight to the blind, it would seem that he can do all.

             5. All resistance is by reason of opposition. But nothing can oppose God's power, as shown above. Therefore nothing can resist it: and so he can do all things impossible.

             6. As blindness is opposed to sight, so is virginity opposed to birth-giving. Now God made a virgin to give birth and yet remain a virgin. Therefore he can equally make a blind man to see while remaining blind, and he can make yes and no to be true at the same time, and consequently all impossible things.

             7. It is more difficult to unite diverse substantial forms, than diverse accidental forms. Now God united together the most diverse substantial forms, namely the divine and human natures, which differ as uncreated and created. Much more, therefore, can he unite two accidental forms, so that the same thing be black and white: and thus the same conclusion follows.

             8. If we deny of the thing defined part of its definition, it will follow that contrary statements are true at the same time; for instance, if we were to say that a man is not a rational being. Now it is part of the definition of a straight line that its extremities are points. Therefore if anyone were to deny this of a straight line, it would follow that two contrary statements are simultaneously true. Now God did this when he came in to his disciples, the doors being closed: since two bodies were then in the same place, so that two lines would have terminated in two points only, and each of them also in two points. Consequently God can make yes and no to be true at the same time, and therefore he can do all things impossible.

             I answer that according to the Philosopher (Metaph. v, 12) a thing is said to be possible or impossible in three ways. First, in respect of a power active or passive: thus it is possible for a man to walk in respect of his ability to walk, whereas it is impossible for him to fly. Secondly, not in respect of a power but in itself: thus we say that a thing is possible if it be not impossible, and that a thing is impossible which of necessity is not. Thirdly, a thing is said to be possible in respect of mathematical power, as we say in geometry; thus a certain line is potentially measurable, because its square is measurable. Omitting this last kind of possibility, let us consider the other two. It must be noted that a thing is said to be impossible, not in respect of any power, but in itself, by reason of the mutual exclusion of terms. Now all such mutual exclusion corresponds to some opposition: and every opposition connotes affirmation and negation, as is proved in Metaph. x, 4, so that all impossibilities of this kind imply the mutual exclusion of an affirmation and a negation. That this cannot be ascribed to any active power is proved as follows. All active power is consequent upon the actuality and entity of the thing to which it belongs. Now every agent has a natural tendency to produce its like: wherefore every act of an active power terminates in being. For although at times non-being is the result of an action, such as, for instance, corruption, this is simply because the being of one thing is incompatible with the being of another; thus the being of a hot thing is incompatible with the being of a cold thing: wherefore the chief purpose of heat is to generate heat, but that it destroys cold is by way of consequence. Now, for yes and no to be true at the same time cannot have the nature of being, nor even of non-being, since being removes non-being, and nonbeing removes being: and consequently it can be neither the principal nor the secondary term of action of an active power.

             On the other hand a thing is said to be impossible in respect of a power in two ways. First, on account of an inherent defect in the power, in that the effect is beyond its reach, as when a natural agent cannot transform a certain matter. Secondly, when the impossibility arises from without, as in the case of a power that is hindered or tied. Accordingly there are three ways in which it is said to be impossible for a thing to be done. First, by reason of a defect in the active power, whether in transforming matter, or in any other way. Secondly, by reason of a resistant or an obstacle. Thirdly, because that which is said to be impossible cannot be the term of an action. Those things, then, which are impossible to nature in the first or second way are possible to God: because, since his power is infinite, it is subject to no defect, nor is there any matter that he cannot transform at will, since his power is irresistible. On the other hand those things which involve the third kind of impossibility God cannot do, since he is supreme act and sovereign being: wherefore his action cannot terminate otherwise than principally in being, and secondarily in nonbeing. Consequently he cannot make yes and no to be true at the same time, nor any of those things which involve such an impossibility. Nor is he said to be unable to do these things through lack of power, but through lack of possibility, such things being intrinsically impossible: and this is what is meant by those who say that 'God can do it, but it cannot be done.'

             Reply to the First Objection. Augustine's words quoted in the gloss mean, not that God is unable to do otherwise than nature does, since his works are often contrary to the wonted course of nature; but that whatever he does in things is not contrary to nature, but is nature in them, forasmuch as he is the author and controller of nature. Thus in the physical order we observe that when an inferior body is moved by a higher, the movement is natural to it, although it may not seem in keeping with the movement which it has by reason of its own nature: thus the tidal movement of the sea is caused by the moon; and this movement is natural to it as the Commentator observes (De coelo et mundo, iii, comm. 20), although water of itself has naturally a downward movement. Thus in all creatures, what God does in them is quasi-natural to them. Wherefore we distinguish in them a twofold potentiality: a natural potentiality in respect of their proper operations and movements, and another, which we call obediential, in respect of what is done in them by God.

             Reply to the Second Objection. Every impossibility involves the incompatibility of affirmation and negation as such. Those things, however, that are impossible by reason of a lack of the natural power, such as that a blind man can be made to see, and the like, since they are not intrinsically impossible, do not involve such an impossibility in themselves, but only in relation to the natural power to which they are impossible. Thus were we to say that nature can make a blind man to see, the statement would involve an impossibility of this kind, because nature's power is confined to definite effects, beyond which is the effect we would ascribe to it.

             Reply to the Third Objection. Philosophical reasoning regards impossibilities not in relation to a power, but in themselves: because it does not consider things in their application to matter or to any natural power.

             Reply to the Fourth Objection. That which is naturally false is false simply; hence there is no comparison.

             Reply to the Fifth Objection. Impossibilities are not all in the same ratio: since some things are impossible in themselves, and some with respect to a power, as above stated. Nor does the fact that they bear different relations to the divine power militate against the infinity of that power, or the obedience of the creature thereto.

             Reply to the Sixth Objection. God does not destroy what is already true: because he does not make that which was true not to have been: but he does make that which otherwise had been true, not to be true. Thus when he raises the dead to life, he makes it to be untrue that he is dead, which would have been true otherwise.--Or we may reply, that there is no comparison, since were God not to keep his promise, it would follow that he is untruthful: whereas this does not follow if he undoes what he has done: because he has not decreed that whatever he does should always remain so, as he has ordained to keep his promise.

             Reply to the Seventh Objection. God cannot make yes and no to be true at the same time, not because it is unbecoming, but for the reason stated above.

             Reply to the Eighth Objection. God's art extends not only to the things made but to many others also. Hence when he changes the course of nature in anything, he does not therefore act against his art.

             Reply to the Ninth Objection. It is accidentally impossible for Socrates not to have run, if he did run: since that Socrates runs or runs not, considered in itself, is a contingency: yet since it would imply that what has been has not been, it becomes impossible in itself. Hence it is said to be impossible accidentally, that is through some adventitious circumstance: which circumstance is impossible in itself, and clearly involves a contradiction: since to say that a thing has been, and that it has not been are contradictory statements: which would be the case if the past were made not to have been.

             Reply to the First Objection on the other side. A word is not only uttered by the lips but is also conceived in the mind. Now the mind cannot conceive yes and no as being true at the same time (Metaph. iv, 3), and therefore it cannot conceive anything in which this is involved. For otherwise since, according to the Philosopher, contrary opinions involve contrary statements, it would follow that the same person would have contrary opinions at the same time. Wherefore it is not contrary to the angel's statement to say that God cannot do the above-mentioned kind of impossibility.

             Reply to the Second Objection. God cannot do this kind of impossibility because it is outside the range of possibility: wherefore God's power is not said to be limited, although he cannot do it.

             Reply to the Third Objection. God is said to be unable to do this, not as though he were prevented by the free-will, as stated above, but because this cannot be the term of action of an active power.

             Reply to the Fourth Objection. Privation as such is not susceptive of degrees, but it can be in respect of its cause: thus a man who has lost an eye is more blind than one who is prevented from seeing by some disease of the eye. In like manner that which is impossible in itself may be said to be more impossible than a thing which is impossible simply.

             Reply to the Fifth Objection. As stated above, God is said to be unable to do this, not because something prevents him, but for the reasons given.

             Reply to the Sixth Objection. Virginity is not opposed to child-bearing as blindness to sight: it is opposed to copulation without which nature cannot cause a child to be born, whereas God can.

             Reply to the Seventh Objection. The created and uncreated, though disparate, were not in Christ in the same respect, but in respect of the different natures: hence it does not follow that God can make opposite things to be in the same subject and in the same respect.

             Reply to the Eighth Objection. When Christ entered, the doors being closed, and two bodies were in the same place, nothing occurred contrary to the principles of geometry. For then not one but two lines terminated in two points of different bodies on the one side. Although two mathematical lines are not distinguishable except by their position, so that one cannot conceive two such lines to be in the same place: nevertheless two natural lines are distinguishable by their subjects, so that, granted that two bodies occupy the same place, it follows that two lines coincide, as well as two points, and two surfaces.