 Clearly, the book addresses the central problems of philosophy which deal with the world, thought and language, and presents a ‘solution’ (as Wittgenstein terms it) of these problems that is grounded in logic and in the nature of representation. The world is represented by thought, which is a proposition with sense, since they all—world, thought, and proposition—share the same logical form. Hence, the thought and the proposition can be pictures of the facts.