Whether blindness of mind is a sin?

❌ Objection 1 : It would seem that blindness of mind is not a sin. Because, seemingly, that which excuses from sin is not itself a sin. Now blindness of mind excuses from sin; for it is written (Jn. 9:41): "If you were blind, you should not have sin." Therefore blindness of mind is not a sin.

❌ Objection 2 : Further, punishment differs from guilt. But blindness of mind is a punishment as appears from Is. 6:10, "Blind the heart of this people," for, since it is an evil, it could not be from God, were it not a punishment. Therefore blindness of mind is not a sin.

❌ Objection 3 : Further, every sin is voluntary, according to Augustine (De Vera Relig. xiv). Now blindness of mind is not voluntary, since, as Augustine says (Confess. x), "all love to know the resplendent truth," and as we read in Eccles. 11:7, "the light is sweet and it is delightful for the eyes to see the sun." Therefore blindness of mind is not a sin.