Fichte
[Kant](/philosophy/thinker/kant) had left a crack in his own system: a world we can never reach, the thing-in-itself, sitting just outside the reach of the knowing mind and yet supposedly causing all our experience. Fichte, who had become famous overnight by being mistaken for Kant in print, decided the crack was the whole problem. He threw the unknowable thing out entirely and tried to build the world from a single starting point that needed nothing outside it: the self, the active I, positing itself into existence by its own act. Everything else, including the entire material world, he tried to derive as something the I sets up over against itself so that it has something to push against. The system he called the Wissenschaftslehre, the Science of Knowledge, starts not from given things but from free activity, and its real ground is not knowing but willing. Idealism, in his hands, stopped being a theory about how the mind colors what it finds and became a theory in which the mind, in the end, makes what it finds. He paid for his independence: an accusation of atheism cost him his chair at Jena, and his life ended in occupied Berlin, lecturing a defeated nation on what it might still be. The triad of terms everyone now hangs on Hegel, thesis and antithesis and synthesis, is actually his.