Logic takes care of itself; all we have to do is to look and see how it does it.

Suppose someone follows the series "1,3,5,7, ..", and in writing the series 2x+1; and he asked himself "But am I always doing the same thing, or something different every time?" If from one day to the next someone promises: "Tomorrow I will give up smoking", does he say the same thing every day, or every day something different?

We regard the photograph, the picture on our wall, as the object itself (the man, landscape, and so on) depicted there. This need not have been so. We could easily imagine people who did not have this relation to such pictures. Who, for example, would be repelled by photographs, because a face without color and even perhaps a face in reduced proportions struck them as inhuman.

Black seems to make a colour cloudy, but darkness doesn't. A ruby could thus keep getting darker without ever becoming cloudy; but if it became blackish red, it would become cloudy.

Genius is talent in which character makes itself heard.

A man will be imprisoned in a room with a door that's unlocked and opens inwards; as long as it does not occur to him to pull rather than push it.

There is not a philosophical method, though there are indeed methods, like different therapies.