It is by his activities and not by enjoyment that man feels he is alive. In idleness we not only feel that life is fleeting, but we also feel lifeless.

Three things tell a man: his eyes, his friends and his favorite quotes

Act that your principle of action might safely be made a law for the whole world.

Both love of mankind, and respect for their rights are duties; the former however is only a conditional, the latter an unconditional, purely imperative duty, which he must be perfectly certain not to have transgressed who would give himself up to the secret emotions arising from benevolence.

In every department of physical science there is only so much science, properly so-called, as there is mathematics.

Two things awe me most, the starry sky above me and the moral law within me.

Each according to his own way of seeing things, seek one goal, that is gratification.