The same fire" (which he decides to be material) " torments the damned in hell and the just in purgatory...The least pain in purgatory exceeds the greatest in this life.

Because we cannot know what God is, but only what He is not, we cannot consider how He is but only how He is not.

The light of faith makes us see what we believe.

To pretend angels do not exist because they are invisible is to believe we never sleep because we don't see ourselves sleeping.

We must love them both, those whose opinions we share and those whose opinions we reject, for both have labored in the search for truth, and both have helped us in finding it.

Reasoning is compared to understanding as movement is to rest, or acquisition to possession.... Since movement always proceeds from something immovable, and ends in something at rest, hence it is that human reasoning, in the order of inquiry and discovery, proceeds from certain things absolutely understood--namely, the first principles; and, again, in the order of judgment, returns by analysis to first principles, in the light of which it examines what it has found. Now it is clear that rest and movement are not to be referred to different powers, but to one and the same.

The celestial bodies are the cause of all that takes place in the sublunar world.