The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.

Because reason...is the only thing that makes us men, and distinguishes us from the beasts, I would prefer to believe that it exists, in its entirety, in each of us.

There is nothing so strange and so unbelievable that it has not been said by one philosopher or another.

So blind is the curiosity by which mortals are possessed, that they often conduct their minds along unexplored routes, having no reason to hope for success, but merely being willing to risk the experiment of finding whether the truth they seek lies there.

An optimist may see a light where there is none, but why must the pessimist always run to blow it out?

What then is the source of my errors? They are owing simply to the fact that, since the will extends further than the intellect, I do not contain the will within the same boundaries; rather, I also extend it to things I do not understand. Because the will is indifferent in regard to such matters, it easily turns away from the true and the good; and in this way I am deceived and I sin.

Everything is self-evident.