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 Obj. 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 Obj. 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 Obj. 4: As stated above (I-II, 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." _______________________
THIRD ARTICLE [II-II, Q. 2, Art. 3]
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.
Obj. 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.
Obj. 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.