God knows the things that are not yet, and then he knows also future contingent singulars
Summa Contra Gentiles, Book I, cc. 66-67
Chapter 66: That God knows the things that are not
1. We must next show that the knowledge even of the things that are not is not lacking to God.
2. As is clear from what we have said above, the relation of the divine knowledge to the things known is the same as the relation of the things that we know to our knowledge. Now, the relation of a thing known to our knowledge is this, namely, that the known thing can exist without our having a knowledge of it, as Aristotle illustrates of the squaring of a circle;[Aristotle, Categories, VII (7b 31)] but the converse is not true. The relation of the divine knowledge to other things, therefore, will be such that it can be even of non-existing things.
3. Again, the knowledge of the divine intellect is to other things as the knowledge of an artisan to artifacts, since through His knowledge God is the cause of things. Now, the artisan knows through his art even those things that have not yet been fashioned, since the forms of his art flow from his knowledge to external matter for the constitution of the artifacts. Hence, nothing forbids that there be in the knowledge of an artisan forms that have not yet come out of it. Thus, nothing forbids God to have knowledge of the things that are not.
4. Furthermore, through His essence God knows things other than Himself in so far as His essence is the likeness of the things that proceed from Him. This is clear from what we have said .[ See above, ch. 49 and 54] But since, as was shown above,[ See above, ch. 43] the essence of God is of an infinite perfection, whereas every other thing has a limited being and perfection, it is impossible that the universe of things other than God equal the perfection of the divine essence. Hence, its power of representation extends to many more things than to those that are. Therefore, if God knows completely the power and perfection of His essence, His knowledge extends not only to the things that are but also to the things that are not.
5. Moreover, by that operation through which it knows what a thing is our intellect can know even those things that do not actually exist. It can comprehend the essence of a lion or a horse even though all such animals were to be destroyed . But the divine intellect knows, in the manner of one knowing what a thing is, not only definitions but also enunciables, as is clear from what we have said.[See above, ch. 58 and 59] Therefore, it can know even the things that are not.
6. Furthermore, an effect can be preknown in its cause even before it exists. Thus, an astronomer preknows a future eclipse motions. But God knows all things through a cause; for, by knowing Himself, Who is the cause of other things, He knows other things as His effects, as was shown above[See above, ch. 49]. Nothing, therefore, prevents God from knowing even the things that are not.
7. Moreover, God's understanding has no succession, as neither does His being. He is therefore an ever-abiding simultaneous whole-which belongs to, the nature of eternity. On the other hand, the duration of time is stretched out through the succession of the before and after. Hence, the proportion of eternity to the total duration of time is as the proportion of the indivisible to something continuous; not, indeed, of that indivisible that is the terminus of a continuum, which is not present to every part of a continuum (the instant of time bears a likeness to such an indivisible), but of that indivisible which is outside a continuum and which nevertheless co-exists with any given part of a continuum or with a determinate point in the continuum. For, since time lies within motion, eternity, which is completely outside motion, in no way belongs to time. Furthermore, since the being of what is eternal does not pass away, eternity is present in its presentiality to any time or instant of time. We may see an example of sorts in the case of a circle. Let us consider a determined point on the circumference of a circle. Although it is indivisible, it does not co-exist simultaneously with any other point as to position, since it is the order of position that produces the continuity of the circumference. On the other hand, the center of the circle, which is no part of the circumference, is directly opposed to any given determinate point on the circumference. Hence, whatever is found in any part of time co exists with what is eternal as being present to it, although with respect to some other time it be past or future. Something can be present to what is eternal only by being present to the whole of it, since the eternal does not have the duration of succession. The divine intellect, therefore, sees in the whole of its eternity, as being present to it, whatever takes place through the whole course of time. And yet what takes place in a certain part of time was not always existent. It remains, therefore, that God has a knowledge of those things that according to the march of time do not yet exist.
8. Through these arguments it appears that God has a knowledge of non-being. But not all non-beings have the same relation to His knowledge. For those things that are not, nor will be, nor ever were, are known by God as possible to His power. Hence, God does not know them as in some way existing in themselves, but as existing only in the divine power. These are said by some to be known by God according to a knowledge of simple understanding. The things that are present, past, or future to us God knows in His power, in their proper causes, and in themselves. The knowledge of such things is said to be a knowledge of vision. For of the things that for us are not yet God sees not only the being that they have in their causes but also the being that they have in themselves, in so far as His eternity is present in its indivisibility to all time.
9. Nevertheless, whatever being a thing has God knows through His essence. For His essence can be represented by many things that are not, nor will be, nor ever were. His essence is likewise the likeness of the power of every cause, through which effects pre-exist in their causes. And the being that each thing has in itself comes from the divine essence as from its exemplary source.
10. Thus, therefore, God knows non-beings in so far as in some way they have being, namely, in His power, or in their causes, or in themselves. This is not incompatible with the nature of knowledge.
11. The authority of Sacred Scripture likewise offers witness to what has preceded. For it is said in Ecclesiasticus (2 3:29): "For all things were known to the Lord God before they were created: so also after they were perfected He beholdeth all things." And in Jeremias (1:5): Before I formed thee in the bowels of thy mother I knew thee.''
12. It is also clear from what has preceded that we are not forced to say, as some said, [The reference is to Avicenna. See above, ch. 63, note] that God knows singulars universally because He knows them only in universal causes, just as one would know a particular eclipse not in itself but as it arises from the position of the stars. For we have shown that the divine knowledge extends to singulars in so far as they are in themselves.
Chapter 67: That God knows future contingent singulars
1. From this we can begin to understand somewhat that God had from eternity an infallible knowledge of contingent singulars, and yet they do not cease to be contingent.
2. The contingent is opposed to the certitude of knowledge only so far as it is future, not so far as it is present. For when the contingent is future, it can not-be. Thus, the knowledge of one conjecturing that it will be can be mistaken: it will be mistaken if what he conjectures as future will not take place. But in so far as the contingent present, in that time it cannot not-be. It can not-be in the future but this affects the contingent not so far as it is present the certitude of sense when someone sees a man running, even though this judgment is contingent. All knowledge, therefore, that bears on something contingent as present can be certain. But the vision of the divine intellect from all eternity is directed o each of the things that take place in the course of time, in so far as it is present, as shown above. [See above, ch. 66.] It remains, therefore, that nothing prevents God from having from all eternity an infallible knowledge of contingents.
3. Again, the contingent differs from the necessary according to the way each of them is found in its cause. The contingent is in its cause in such a way that it can both not-be and be from it; but the necessary can only be from its cause. But according to the way both of them are in themselves, they do not differ as to being, upon which the true is founded. For, according as it is in itself the contingent cannot be and not-be, it can only be, even though in the future it can not-be. Now, the divine intellect from all eternity knows things not only according to the being that they have in their causes, but also according to the being that they have in themselves. Therefore, nothing prevents the divine intellect from having an eternal and infallible knowledge of contingents.
4. Moreover, just as from a necessary cause an effect follows with certitude, so it follows from a complete contingent cause if it be not impeded. But since, as appears from what was said above, [ See above, ch . 50] God knows all things, He knows not only the causes of contingent things but also those things by which these causes may be impeded. Therefore, He knows with certitude whether contingent things are or are not.
5. Furthermore, an effect cannot exceed the perfection of its cause, though sometime it falls short of it. Hence, since our knowledge comes to us from things, it happens at times that we know what is necessary not according to the mode of necessity but according to that of probability. Now, just as in us things are the cause of knowledge, so the divine knowledge is the cause of the things known. Therefore, nothing prevents those things from being contingent in themselves of which God has a necessary knowledge.
6. Again, an effect whose cause is contingent cannot be a necessary one; otherwise, the effect could be even though the cause were removed. Now, of the most remote effect there is both a proximate and a remote cause. If, then, the proximate cause were contingent, its effect would have to be contingent even though the remote cause is necessary. Thus, plants do not bear fruit of necessity, even though the motion of the sun is necessary, because the intermediate causes are contingent. But the knowledge of God, though it is the cause of the things known through it, is yet a remote cause. Therefore, the contingency of the things known is not in conflict with this necessity, since it may be that the intermediate causes are contingent.
7. The knowledge of God, furthermore, would not be true and perfect if things did not happen the way in which God knows them to happen. Now, since God knows all being, and is its source, He knows every effect not only in itself but also in its order to each of its causes. But the order of contingent things to their proximate causes is that they come forth from these causes in a contingent way. Hence, God knows that some things are taking place, and this contingently. Thus, therefore, the certitude and truth of the divine knowledge does not remove the contingency of things.
8. From what has been said, it is therefore clear how the objection impugning a knowledge of contingents in God is to be repulsed. For change in that which comes later does not induce change in that which has preceded; for it is possible that from prime necessary causes ultimate contingent effects. Now, the things that are known by God are not prior to His knowledge, as is the case with us, but, rather, subsequent to it. It does not therefore follow that, if something known by God can change, His knowledge of it can be deceived or in any way changed. We shall be deceived in the consequent therefore, If, because our knowledae of changeable things is itself changeable, we suppose on this account that such is necessarily the case in all knowledge.
9. Again, when it is said that God knows or knew this future thing, a certain intermediate point between the divine knowledge and the thing known is assumed. This is the time when the above words are spoken, in relation to which time that which is known by God is said to be future. But this is not future with reference to the divine knowledge, which, abiding in the moment of eternity, is related to all things as present to them. If with respect to the divine knowledge we remove from its intermediate position the time when the words are spoken, we cannot say that this is known by God as non-existent, so as to leave room for the question whether it can not-be; rather, it will be said to be known by God in such a way that it is seen by Him already in its own existence. On this basis there is no room for the preceding question. For that which already is cannot, with respect to that moment of time, not be. We are therefore deceived by the fact that the time in which we are speaking is present to eternity, as is likewise past time (designated by the words God knew). Hence, the relation of past or present time to the future is attributed to eternity, to which such a relation does not belong. It is thus that we commit the fallacy of accident.
10. There is more. If each thing is known by God as seen by Him in the present, what is known by God will then have to be. Thus, it is necessary that Socrates be seated from the fact that he is seen seated. But this is not absolutely necessary or, as some say, with the necessity of the consequent; it is necessary conditionally, or with the necessity of the consequence. For this is a necessary conditional proposition: if he is seen sitting, he is sitting. Hence, although the conditional proposition may be changed to a categorical one, to read what is seen sitting must necessarily be sitting, it is clear that the proposition is true if understood of what is said, and compositely; but it is false if understood of what is meant, and dividedly. Thus, in these and all similar arguments used by those who oppose God's knowledge of contingents, the fallacy of composition and division takes place.
11. That God knows future contingents is also shown by the authority of Sacred Scripture. For it is said of the divine wisdom: "Se they be done, and the events of times and ages" (Wis. 8 :8). And in Ecclesiasticus (39:24-25) it is said: "There is nothing hid from His eyes. He seeth from eternity to eternity”. And Isaias (48:5): “I foretold thee of old, before they came to pass I told thee.”
Summa contra Gentiles, Book I, cc. 66-67, translated by Anton C. Pegis (Notre Dame - London: University of Notre Dame Press, 1975), pp. 217-225.