One can mistrust one's own senses, but not one's own belief.

Think of the tools in a tool-box: there is a hammer, pliers, a saw, a screwdriver, a rule, a glue-pot, nails and screws.--The function of words are as diverse as the functions of these objects.

We find certains things about seeing puzzling, because we do not find the whole business of seeing puzzling enough.

All mathematics is tautology.

The philosophical I is not the human being, not the human body or the human soul with the psychological properties, but the metaphysical subject, the boundary (not a part) of the world.

Courage, not cleverness; not even inspiration, is the grain of mustard that grows up to be a great tree.

To convince someone of the truth, it is not enough to state it, but rather one must find the path from error to truth.