All mathematics is tautology.

A picture whose pictorial form is logical form is called a logical picture.

The depressed man lives in a depressed world.

A tautology's truth is certain, a proposition's possible, a contradiction's impossible.

Is my understanding only blindness to my own lack of understanding? It often seems so to me.

There is a truth in Schopenhauer’s view that philosophy is an organism, and that a book on philosophy, with a beginning and end, is a sort of contradiction. ... In philosophy matters are not simple enough for us to say ‘Let’s get a rough idea’, for we do not know the country except by knowing the connections between the roads.

A serious and good philosophical work could be written consisting entirely of jokes.