It would seem that the ingratitude, whereby a subsequent sin causes the return of sins previously forgiven, is a special sin. For, the giving of thanks belongs to counter passion, which is a necessary condition of justice. But justice is a special virtue. Therefore this ingratitude is a special sin. Thanksgiving is a special virtue. But ingratitude is opposed to thanksgiving. Therefore ingratitude is a special sin.

When fear is excessive it can make many a man despair.

If forgers and malefactors are put to death by the secular power, there is much more reason for excommunicating and even putting to death one convicted of heresy.

What can be accomplished by a few principles is not effected by many. But it seems that everything we see in the world can be accounted for by other principles, supposing God did not exist. For all natural things can be reduced to one principle, which is nature, and all voluntary things can be reduced to one principle, which is human reason, or will. Therefore there is no need to suppose God's existence.

Wonder was the motive that led people to philosophy ... wonder is a kind of desire in knowledge. It is the cause of delight because it carries with it the hope of discovery.

He who achieves power by violence does not truly become lord or master.

Charity is the form, mover, mother and root of all the virtues.