To what extent did mature Wittgenstein disagree with young Wittgenstein? Some of the continuity between them was unavoidable. They shared the therapy that anti-philosophy is supposed to provide. Young Wittgenstein criticized Russell to the point of making him abandon his major research project that included the search for certainty. This search followed two major ideas, logicism and logical atomism (Bar-Elli G: Analysis without elimination: on the philosophical significance of Russell's "On denoting". Matar and Biletzki (eds), pp 167–81, 2002, 170). Both failed. Young Wittgenstein persisted. His system was version of neutral monism cast in the language of modern logic.