In 1807 and 1808 he delivered in Berlin his famous Addresses to the German Nation, which were aimed at Stirring up the patriotic spirit of his countrymen and enlightening them on the foundations for national prosperity. Fichte died of typhus in 1814. His masterpiece is Foundation of General Science. As an answer Criticism had advanced the doctrine of the thinking ego, which organizes the data of experience according to subjective a priori forms. For Fichte, on the contrary, the ego is creative activity and the root of all reality.
Nothing is presupposed to the ego.
In the very act by which the ego affirms that it is thinking there are contained, implicitly, all the causes of the phenomena, and nature in its totality. Fichte thus abolishes Kant's dualism of subject and object, of form and matter, of thought and being. Object, matter and noumenon will depend upon the activity of the Pure Ego. To know nature is equivalent to knowing the process by which nature is derived from Pure Ego. Instead, the new Idealism, regarding things as being produced by the conscious activity of the ego, derives them from the world of liberty.