A thought is a sentence that made sense.

Thoughts are sentences that make sense. In their entirety, they constitute language. Mankind constructs languages that allow one to express any sense without needing to have much of an idea what each particular word means or how that is so. This is also just how one speaks, without knowing how individual sounds are made. Natural language is a bodily function and no less complicated than that body. It is not humanly possible to directly obtain the logic of natural language from itself.

Language disguises thought, so that one cannot infer, from the outward form of the clothing, the form of the thought clothed by it. This is so, because the outward form of the clothing is designed for entirely different purposes than to let the form of the body be recognized and the tacit conventions that are part of understanding natural language are so complex.

Most of the statements and questions to be found in philosophical works are not false; they just make no sense. Consequently we cannot give any answer to questions of this kind, but can only point out that they do not make sense. (They belong to the same class as the question whether the good is more or less identical than the beautiful.) Most of the propositions and questions of philosophers arise from our failure to understand the logic of our language and it is not surprising that the deepest problems are in fact not problems at all.

All philosophy is a 'linguistic critique' (though not in Mauthner's sense). Russell's achievement was to show that the apparent logical form of a proposition need not be its real one.