Wittgenstein subscribed to picture theory of meaning in Tractatus Logico-Philosophicus. According to this theory, we are only allowed to talk about state of affairs and whatever belongs to natural science meaningfully. Beyond natural sciences which consist of ethics, logic, religion, mathematics.. .nothing can be said, semantically speaking. According to Wittgenstein, the main task of philosophy is to clarify the distinction between saying and showing: What cannot be talked about, we must pass over in silence.In this article, firstly, picture theory of meaning is explained. Secondly, different accounts of the very idea of silence which is cited in the last section of Tractatus Logico-Philosophicus are presented as follow: neutral silence, negative silence, mystical silence and therapeutic silence.