We proceed to the eighth article thus:

1. It seems that faith is not more certain than science and the other intellectual virtues. For doubt is opposed to certainty, wherefore that is apparently the more certain which is the less open to doubt, just as that is the whiter which is the less mixed with black. Now understanding and science, and even wisdom, have no doubts about their objects. But one who believes may be subject to intermittent doubt, and may have doubts concerning matters of faith. It follows that faith is not more certain than the intellectual virtues.

2. Again, vision is more certain than hearing. Now it is said in Rom.10:17 that "faith cometh by hearing." In understanding, science, and wisdom, on the other hand, there is a kind of intellectual vision. It follows that science, or understanding, is more perfect than faith.

3. Again, in matters pertaining to the intellect, things are more certain if they are more perfect. Now understanding is more perfect than faith, since we advance to understanding through faith, according to Isa.7:9: "Except ye believe, ye shall not understand" (Septuagint). Moreover, Augustine says that "faith is strengthened by science" (14 De Trin.1). Hence it appears that science and understanding are more certain than faith.

On the other hand: the apostle says in I Thess.2:13: "when ye received the word of God which ye heard of us," that is, through faith, "ye received it not as the word of men, but, as it is in truth, the word of God." Now nothing is more certain than the word of God. Hence neither science nor anything else is more certain than faith.

I answer: as we said in 12ae, Q.62, Art.4, ad.2, two of the intellectual virtues, namely prudence and art, are concerned with the contingent. Faith is more certain than either of these by reason of its very matter, since it is concerned with the eternal, which cannot be other than it is. There remain, then, the three intellectual virtues of wisdom, science, and understanding, which are concerned with the necessary, as we said in 12ae, Q.57, Arts.2 and 3. We must observe, however, that wisdom, science, and understanding may be understood in two ways. As understood by the philosopher in 6 Ethics 3, 6, and 7, they denote intellectual virtues. But they also denote gifts of the Holy Spirit.

There are two kinds of certainty which belong to them as intellectual virtues. In the first place, a thing is said to be more certain if the cause of certainty is itself more certain. Faith is in this sense more certain than the three virtues named, since it relies on divine truth, whereas they rely on human reason. Secondly, the assurance of the subject is more certain when the intellect grasps a thing more fully. In this sense, faith is less certain than these virtues, since the things of faith transcend the intellect of man, whereas the virtues named are concerned with what does not transcend it. Now a thing is judged absolutely by reference to its cause, and relatively by reference to the disposition of the subject. In the absolute sense, therefore, faith is the more certain, although these others are more certain relatively, that is, from the point of view of ourselves.

The case is similar if these three are understood to denote divine gifts given to us in this present life. Faith is more certain than such gifts, since they presuppose faith as their principle.

On the first point: this doubt does not pertain to the cause of faith. It pertains to ourselves, in so far as the intellect does not fully grasp the things of faith.

On the second point: other things being equal, vision is more certain than hearing. But if he from whom one hears greatly surpasses the vision of him who sees, hearing is more certain than vision. Indeed, anyone who has a little learning is more certain of what he hears from a scientist than of what he perceives by his own reason. Much more, then, is a man more certain of what he hears from God, which cannot be false, than of what he perceives by his own reason, which is liable to err.

On the third point: as divine gifts, perfect understanding and knowledge surpass the knowledge of faith in clarity, but not in certainty. For their certainty is the outcome of the certainty of faith, just as certainty of a conclusion is the outcome of certainty of the premises. As intellectual virtues, on the other hand, knowledge, wisdom, and understanding depend on the natural light of reason, which falls short of the certainty of the word of God, on which faith relies.