I act with complete certainty. But this certainty is my own.

If people did not sometimes do silly things, nothing intelligent would ever get done.

Russell's books should be bound in two colours, those dealing with mathematical logic in red - and all students of philosophy should read them; those dealing with ethics and politics in blue - and no one should be allowed to read them.

Our greatest stupidities may be very wise.

The truth of the thoughts that are here set forth seems to me unassailable and definitive. I therefore believe myself to have found, on all essential points, the final solution of the problems. And if I am not mistaken in this belief, then the second thing in which the value of this work consists is that it shows how little is achieved when these problems are solved.

For an answer which cannot be expressed the question too cannot be expressed. The riddle does not exist. If a question can be put at all, then it can also be answered.

The solution to the problem of life is seen in the vanishing of this problem.