Wittgenstein's early philosophy can be characterized as phenomenology in the sense that his aim was to describe the world as it is, without any hypotheses, just as phenomenological physicists like Mach. But for him the world ("the world we live in") is a phenomenological world. Hence hypothesis-free description and phenomenological description became for Wittgenstein to mean the same thing. According to Wittgenstein, the phenomenological world consists of phenomenological objects that can be picked out by the words "this' and "that' with pointing gestures, which would give immediate description of immediate experience. As his middle-period writings show, the words "this' and "that' are without hypothesis and thus pure and primary. But he notices that the logical behavior of these words, along with "here', "now', and "I', easily prompt solipsistic interpretations. So after the rejection of phenomenological language, he tries to examine how the logic of these words is related to solipsism and how we can prevent any expressions from becoming solipsistic. As long as solipsism is merely construed as a special notation within the overall physicalistic notations, it can be rendered harmless. But if it is thought of as leading to purely phenomenological language, Wittgenstein has to disarm it. His discussion of solipsism is thus only one aspect of his defense of his new vision of language and its relation to the world.