The investigation of the truth is in one way hard, in another easy.

Those who wish to succeed must ask the right preliminary questions.

It is not once nor twice but times without number that the same ideas make their appearance in the world.

Change is the most fundamental aspect of reality.

The universal is the common predicate of several subjects.

It must be nature, culture and human reason that commands what is good and bad.

The primary philosophy (Metaphysics) is universal and is exclusively concerned with primary substance.

The final cause, then, produces motion by being loved, but all other things move by being moved.

Actual knowledge is identical to its object.

The ultimate value of life depends upon awareness and the power of contemplation rather than upon mere survival.