Logic must look after itself. In a certain sense, we cannot make mistakes in logic.

A philosophical problem has the form: I don't know my way about.

The feeling of an unbridgeable gulf between consciousness and brain-process:When does this feeling occur in the present case?It is when I (for example) turn my attention in a particular way on to my own consciousness, and, astonished, say to myself: THIS is supposed to be produced by a process in the brain!--as it were clutching my forehead.

When we think about the future of the world, we always have in mind its being where it would be if it continued to move as we see it moving now. We do not realize that it moves not in a straight line and that its direction changes constantly.

In order to draw a limit to thinking, we should have to think both sides of this limit.

The world is the totality of facts, not of things

Don't get involved in partial problems, but always take flight to where there is a free view over the whole single great problem, even if this view is still not a clear one.