Quote by Frege, Gottlob
"One should distinguish between the sense and the reference of a sign."
More from Frege, Gottlob
"A thought is a proposition which we apprehend."
"The word 'number' is surely not without a sense; but when we have the sentence 'the number of roots of this equation is four', it seems very difficult to give the meaning of the word 'number' here."
"Functions are concepts; concepts are functions."
"The content of a thought may have different kinds of parts."