Objection 2: Further, that which is common to all acts of faith should not be reckoned as a particular kind of act of faith. Now "to believe God" is common to all acts of faith, since faith is founded on the First Truth. Therefore it seems unreasonable to distinguish it from certain other acts of faith.
Objection 3: Further, that which can be said of unbelievers, cannot be called an act of faith. Now unbelievers can be said to believe in a God. Therefore it should not be reckoned an act of faith.
Objection 4: Further, movement towards the end belongs to the will, whose object is the good and the end. Now to believe is an act, not of the will, but of the intellect. Therefore "to believe in God," which implies movement towards an end, should not be reckoned as a species of that act.
On the contrary is the authority of Augustine who makes this distinction (De Verb. Dom., Serm. lxi---Tract. xxix in Joan.).
I answer that, The act of any power or habit depends on the relation of that power or habit to its object. Now the object of faith can be considered in three ways. For, since "to believe" is an act of the intellect, in so far as the will moves it to assent, as stated above (A[1], ad 3), the object of faith can be considered either on the part of the intellect, or on the part of the will that moves the intellect.
If it be considered on the part of the intellect, then two things can be observed in the object of faith, as stated above (Q[1], A[1]). One of these is the material object of faith, and in this way an act of faith is "to believe in a God"; because, as stated above (Q[1], A[1]) nothing is proposed to our belief, except in as much as it is referred to God. The other is the formal aspect of the object, for it is the medium on account of which we assent to such and such a point of faith; and thus an act of faith is "to believe God," since, as stated above (Q[1], A[1]) the formal object of faith is the First Truth, to Which man gives his adhesion, so as to assent to Its sake to whatever he believes.
Thirdly, if the object of faith be considered in so far as the intellect is moved by the will, an act of faith is "to believe in God." For the First Truth is referred to the will, through having the aspect of an end.
Reply to Objection 1: These three do not denote different acts of faith, but one and the same act having different relations to the object of faith.
This suffices for the Reply to the Second Objection.
Reply to Objection 3: Unbelievers cannot be said "to believe in a God" as we understand it in relation to the act of faith. For they do not believe that God exists under the conditions that faith determines; hence they do not truly imply believe in a God, since, as the Philosopher observes (Metaph. ix, text. 22) "to know simple things defectively is not to know them at all."
Reply to Objection 4: As stated above (FS, Q[9], A[1]) the will moves the intellect and the other powers of the soul to the end: and in this respect an act of faith is "to believe in God."
Whether it is necessary for salvation to believe anything above the natural reason?
Objection 1: It would seem unnecessary for salvation to believe anything above the natural reason. For the salvation and perfection of a thing seem to be sufficiently insured by its natural endowments. Now matters of faith, surpass man's natural reason, since they are things unseen as stated above (Q[1], A[4]). Therefore to believe seems unnecessary for salvation.
Objection 2: Further, it is dangerous for man to assent to matters, wherein he cannot judge whether that which is proposed to him be true or false, according to Job 12:11 : "Doth not the ear discern words?" Now a man cannot form a judgment of this kind in matters of faith, since he cannot trace them back to first principles, by which all our judgments are guided. Therefore it is dangerous to believe in such matters. Therefore to believe is not necessary for salvation.
Objection 3: Further, man's salvation rests on God, according to Ps. 36:39 : "But the salvation of the just is from the Lord." Now "the invisible things" of God "are clearly seen, being understood by the things that are made; His eternal power also and Divinity," according to Rom. 1:20 : and those things which are clearly seen by the understanding are not an object of belief. Therefore it is not necessary for man's salvation, that he should believe certain things.
On the contrary, It is written ( Heb. 11:6 ): "Without faith it is impossible to please God."
I answer that, Wherever one nature is subordinate to another, we find that two things concur towards the perfection of the lower nature, one of which is in respect of that nature's proper movement, while the other is in respect of the movement of the higher nature. Thus water by its proper movement moves towards the centre (of the earth), while according to the movement of the moon, it moves round the centre by ebb and flow. In like manner the planets have their proper movements from west to east, while in accordance with the movement of the first heaven, they have a movement from east to west. Now the created rational nature alone is immediately subordinate to God, since other creatures do not attain to the universal, but only to something particular, while they partake of the Divine goodness either in "being" only, as inanimate things, or also in "living," and in "knowing singulars," as plants and animals; whereas the rational nature, in as much as it apprehends the universal notion of good and being, is immediately related to the universal principle of being.
Consequently the perfection of the rational creature consists not only in what belongs to it in respect of its nature, but also in that which it acquires through a supernatural participation of Divine goodness. Hence it was said above (FS, Q[3], A[8]) that man's ultimate happiness consists in a supernatural vision of God: to which vision man cannot attain unless he be taught by God, according to Jn. 6:45 : "Every one that hath heard of the Father and hath learned cometh to Me." Now man acquires a share of this learning, not indeed all at once, but by little and little, according to the mode of his nature: and every one who learns thus must needs believe, in order that he may acquire science in a perfect degree; thus also the Philosopher remarks (De Soph. Elench. i, 2) that "it behooves a learner to believe."
Hence in order that a man arrive at the perfect vision of heavenly happiness, he must first of all believe God, as a disciple believes the master who is teaching him.
Reply to Objection 1: Since man's nature is dependent on a higher nature, natural knowledge does not suffice for its perfection, and some supernatural knowledge is necessary, as stated above.
Reply to Objection 2: Just as man assents to first principles, by the natural light of his intellect, so does a virtuous man, by the habit of virtue, judge aright of things concerning that virtue; and in this way, by the light of faith which God bestows on him, a man assents to matters of faith and not to those which are against faith. Consequently "there is no" danger or "condemnation to them that are in Christ Jesus," and whom He has enlightened by faith.
Reply to Objection 3: In many respects faith perceives the invisible things of God in a higher way than natural reason does in proceeding to God from His creatures. Hence it is written ( Ecclus. 3:25 ): "Many things are shown to thee above the understandings of man."
Whether it is necessary to believe those things which can be proved by natural reason?
Objection 1: It would seem unnecessary to believe those things which can be proved by natural reason. For nothing is superfluous in God's works, much less even than in the works of nature. Now it is superfluous to employ other means, where one already suffices. Therefore it would be superfluous to receive by faith, things that can be known by natural reason.
Objection 2: Further, those things must be believed, which are the object of faith. Now science and faith are not about the same object, as stated above (Q[1], AA[4],5). Since therefore all things that can be known by natural reason are an object of science, it seems that there is no need to believe what can be proved by natural reason.