Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. Dionysius says that cognition is had only of existing things. But that which neither is nor will be nor has been does not exist in any way. Hence, God cannot have knowledge of such a thing.

2. All cognition takes place through an assimilation of the knower to the thing known. But the divine intellect cannot be assimilated to a non-being. Hence, it cannot know a non-being.

3. God's knowledge of things is through ideas. But there is no idea of a non-being. Hence, God does not know a non-being.

4. Whatever God knows is in His Word. But, as Anselm says: "There is no word for that which neither is, was, nor will be." Hence, God does not know non-beings.

5. God knows only the true. But the true and being are interchangeable. Hence, God does not know things that do not exist.

To the Contrary:

According to the Epistle to the Romans (4:17): "He calls things that are not as though they were." But God would not call non-beings beings unless He knew them. Therefore, He knows non-beings.

REPLY:

God's knowledge of created things may be compared to that which an artist has of his artistic products and which is their cause. Hence, the relation of God's knowledge to things known is the opposite of the relation of our knowledge to them. Our knowledge is received from things, and, by its nature, comes after them. But the Creator's knowledge of creatures, and the artist's of his products, by its very nature, precedes the things known. Now, when what is antecedent is removed, what is subsequent is likewise removed; but the opposite is not true. Hence, our knowledge of natural things cannot be had unless these things previously exist; but the actual existence or non-existence of a thing is a matter of indifference to the intellect of God or that of an artist.

We must remark, however, that an artist has two kinds of knowledge about something that can be made: speculative and practical. He has speculative or theoretical knowledge when he knows the intimate nature of a work but does not have the intention of applying the principles to the production of the work. His knowledge is practical, properly speaking, when by his intention he ordains the principles of the work to operation as an end. In this way, as Avicenna says, medicine is divided into theoretical and practical.

It is clear that the practical knowledge of an artist follows his speculative knowledge, since it is made practical by applying the speculative to a work. But when the practical is absent, the speculative remains. Evidently, then, an artist can have knowledge of some work which he sometimes sets about making and sometimes does not, as when he thinks up the form of some piece of handicraft which he does not intend to make. Moreover, the artist does not always regard this work which he does not take steps to make as something within his power; for sometimes he visualizes a type of device entirely beyond his power of making. He regards it rather in the light of his own purposes, that is, he sees that he could attain such and such an end by means of such and such a device. For, as the Philosopher says, in the order of things to be done, ends are as principles are in the order of things to be studied; hence, as conclusions are known in their principles, products of art are known in the light of their purposes.

It is clear, therefore, that God can know some non-beings. Of some He has, as it were, practical knowledge--that is, of those which are, have been, or will be; and these come forth from His knowledge as He decides. Of those which neither have been, are, nor will be--which He has decreed never to make--He has a kind of speculative knowledge. And although one can say that He sees these things as within His power, since there is nothing He cannot do, it is more appropriate to say that He sees them in His goodness, the end of all that is made by Him; for He sees that there are many other ways of communicating His goodness, besides those He has already communicated to existing things, having existence, past, present, or future, because all created things cannot equal His goodness, no matter how much they seem to participate in it.

Answers to Difficulties:

1. Things which neither have been, are, nor will be, exist in some way in God's power as in an active principle, or in His goodness as in a final cause.

2. Knowledge received from things known consists in a passive assimilation by which the knower is assimilated to objects of knowledge previously existing. But knowledge which is the cause of things known consists in an active assimilation by which the knower assimilates the thing known to himself. Since God can assimilate to Himself that which has not yet been assimilated to Him, He can also have knowledge of non-being.

3. If, according to common usage, idea is taken as meaning the form of practical knowledge, then there is an idea only of those things which have been, are, or will be. If it be taken as also meaning the form of speculative knowledge, then there can also be an idea of other things--those things which neither are, have been, nor will be.

4. The Word designates the operative power of the Father by which all His operations take place. Hence, the Word is extended only to those things to which the divine operation is extended. Consequently, we read in the Psalms (32:9): "He spoke and they were made." For, although the Word knows other beings, it is not the word of other beings.

5. Things which neither have been, are, nor will be possess truth in so far as they possess existence, namely, in so far as they are in their active principle or final cause. As such, they are also known by God.