I give no sources, because it is indifferent to me whether what I have thought has already been thought before me by another. - Ludwig Wittgenstein

"What the names signify must be indestructible; for it must be possible to receive a state of affairs in which everything destructible is destroyed. And this description will contain words; and what corresponds to these cannot be destroyed, for otherwise the words would have no meaning." I must not saw off the branch on which I am sitting.

Certainty is as it were a tone of voice in which one declares how things are, but one does not infer from the tone of voice that one is justified.

I really do think with my pen, because my head often knows nothing about what my hand is writing.