I answer that, The thing known is in the knower according to the mode of the knower. Now the mode proper to the human intellect is to know the truth by synthesis and analysis, as stated in the First Part (Q. 85, A. 5). Hence things that are simple in themselves, are known by the intellect with a certain amount of complexity, just as on the other hand, the Divine intellect knows, without any complexity, things that are complex in themselves.
Accordingly the object of faith may be considered in two ways. First, as regards the thing itself which is believed, and thus the object of faith is something simple, namely the thing itself about which we have faith. Secondly, on the part of the believer, and in this respect the object of faith is something complex by way of a proposition.
Hence in the past both opinions have been held with a certain amount of truth.
Reply Obj. 1: This argument considers the object of faith on the part of the thing believed.
Reply Obj. 2: The symbol mentions the things about which faith is, in so far as the act of the believer is terminated in them, as is evident from the manner of speaking about them. Now the act of the believer does not terminate in a proposition, but in a thing. For as in science we do not form propositions, except in order to have knowledge about things through their means, so is it in faith.
Reply Obj. 3: The object of the heavenly vision will be the First Truth seen in itself, according to 1 John 3:2: "We know that when He shall appear, we shall be like to Him: because we shall see Him as He is": hence that vision will not be by way of a proposition but by way of a simple understanding. On the other hand, by faith, we do not apprehend the First Truth as it is in itself. Hence the comparison fails. _______________________
THIRD ARTICLE [II-II, Q. 1, Art. 3]
Whether Anything False Can Come Under Faith?
Objection 1: It would seem that something false can come under faith. For faith is condivided with hope and charity. Now something false can come under hope, since many hope to have eternal life, who will not obtain it. The same may be said of charity, for many are loved as being good, who, nevertheless, are not good. Therefore something false can be the object of faith.
Obj. 2: Further, Abraham believed that Christ would be born, according to John 8:56: "Abraham your father rejoiced that he might see My day: he saw it, and was glad." But after the time of Abraham, God might not have taken flesh, for it was merely because He willed that He did, so that what Abraham believed about Christ would have been false. Therefore the object of faith can be something false.