Whether without grace man can know any truth?

❌ Objection 1 : It would seem that without grace man can know no truth. For, on 1 Cor. 12:3: "No man can say, the Lord Jesus, but by the Holy Ghost," a gloss says: "Every truth, by whomsoever spoken is from the Holy Ghost." Now the Holy Ghost dwells in us by grace. Therefore we cannot know truth without grace.

❌ Objection 2 : Further, Augustine says (Solil. i, 6) that "the most certain sciences are like things lit up by the sun so as to be seen. Now God Himself is He Whom sheds the light. And reason is in the mind as sight is in the eye. And the eyes of the mind are the senses of the soul." Now the bodily senses, however pure, cannot see any visible object, without the sun's light. Therefore the human mind, however perfect, cannot, by reasoning, know any truth without Divine light: and this pertains to the aid of grace.

❌ Objection 3 : Further, the human mind can only understand truth by thinking, as is clear from Augustine (De Trin. xiv, 7). But the Apostle says (2 Cor. 3:5): "Not that we are sufficient to think anything of ourselves, as of ourselves; but our sufficiency is from God." Therefore man cannot, of himself, know truth without the help of grace.