Things which we see are not by themselves what we see ... It remains completely unknown to us what the objects may be by themselves and apart from the receptivity of our senses. We know nothing but our manner of perceiving them.

Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

I feel a complete thirst for knowledge and an eager unrest to go further in it as well as satisfaction at every acquisition. There was a time when I believed that this alone could constitute the honor of mankind, and I had contempt for the ignorant rabble who know nothing.

Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.

There is something splendid about innocence; but what is bad about it, in turn, is that it cannot protect itself very well and is easily seduced.

I am an investigator by inclination. I feel a great thirst for knowledge.

The only thing that is good without qualification is a good will.