 As a systematic counterpart to the construction of the phenomena of nature out of different dynamic factors (forces, activities), in 1800 Schelling presented his System of Transcendental Idealism. Here he set out to demonstrate the development of mental phenomena out of these factors which he here calls the unconscious and the conscious activity starting with sensation (Empfindung) and intuition (Anschauung) until he arrives via acts of willing at the aesthetic activity manifested in works of art. He thinks of these transcendental idealistic demonstrations as a necessary complement to his philosophy of nature (cf. SW III, 331 f.) and describes their mutual relation thus: