Your discovery of the contradiction caused me the greatest surprise and, I would almost say, consternation, since it has shaken the basis on which I intended to build my arithmetic.
Gottlob FregeThe aim of scientific work is truth. While we internally recognise something as true, we judge, and while we utter judgements, we assert.
Gottlob Frege...one can hardly deny that mankind has a common store of thoughts which is transmitted from one generation to another.
Gottlob FregeIt really is worth the trouble to invent a new symbol if we can thus remove not a few logical difficulties and ensure the rigour of the proofs. But many mathematicians seem to have so little feeling for logical purity and accuracy that they will use a word to mean three or four different things, sooner than make the frightful decision to invent a new word.
Gottlob Frege