“[Philosophy] must set limits to what can be thought; and, in doing so, to what cannot be thought. It must set limits to what cannot be thought by working outwards through what can be thought.”

“We cannot therefore say in logic: This and this there is in the world, that there is not.For that would apparently presuppose that we exclude certain possibilities, and this cannot be the case since otherwise logic must get outside the limits of the world: that is, if it could consider these limits from the other side also.”

“What can be shown, cannot be said.”

“Everything that can be thought at all can be thought clearly. Everything that can be said can be said clearly.”

“Language disguises the thought; so that from the external form of the clothes one cannot infer the form of the thought they clothe, because the external form of the clothes is constructed with quite another object than to let the form of the body be recognized.”

“It is not humanly possible to gather immediately from it what the logic of language is. Language disguises thought.”

“I give no sources, because it is indifferent to mewhether what I have thought has already beenthought before me by another.”