Abstract
It was Paul Engelmann who stimulated Wittgenstein to consider art as the avenue of access to what is higher, the "mystical" in the Tractatus. Unlike the course of their personal friendship, it is not easy to reconstruct the nature of their philosophical confrontation with one another. In the light of their correspondence, Wittgenstein's notebooks and the bit we know from biographers, Wittgenstein's development in the period immediately before he met Engelmann is sketched, discussing the influence of Hertz and Weininger, and determining what his meeting with Engelmann meant for his philosophy.