Whether ignorance excuses from sin altogether?

❌ Objection 1 : It would seem that ignorance excuses from sin altogether. For as Augustine says (Retract. i, 9), every sin is voluntary. Now ignorance causes involuntariness, as stated above (Question [6], Article [8]). Therefore ignorance excuses from sin altogether.

❌ Objection 2 : Further, that which is done beside the intention, is done accidentally. Now the intention cannot be about what is unknown. Therefore what a man does through ignorance is accidental in human acts. But what is accidental does not give the species. Therefore nothing that is done through ignorance in human acts, should be deemed sinful or virtuous.

❌ Objection 3 : Further, man is the subject of virtue and sin, inasmuch as he is partaker of reason. Now ignorance excludes knowledge which perfects the reason. Therefore ignorance excuses from sin altogether.