Hegel's Absolute Idealism versus Schelling and Fichte

Johann Gottlieb Fichte's Wissenschaftslehre (Doctrine of Science), first presented in 1794–1795 and repeatedly reworked over his career, grounded all of philosophy in the self-positing activity of an absolute I (Ich): the I posits itself as an original, free act (Tathandlung, or 'deed-act'), and then posits a Not-I (Nicht-Ich) as an opposing object, from which the finite, limited self and the world of ordinary experience are supposed to be derived. This is a form of 'subjective idealism' in which the Absolute is conceived fundamentally as a subject or activity rather than as a static substance.