Practical sciences proceed by building up; theoretical science by resolving into components.

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.

Now it seems that everything in the world stems from sources other than God, since the products of nature have their source in nature; deliberate effects can be traced back to human reason or will as their source. There is no need then to assume that God exists.

Theology is taught by God, teaches God, and leads to God.

The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false.

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.

Arrive at knowledge over small streamlets, and do not plunge immediately into the ocean, since progress must go from the easier to the more difficult.