 Fichte’s dynamic conception of idealism was adopted almost immediately by Friedrich Wilhelm Joseph Schelling (1775–1854), who in the first period of his philosophical career became next to Fichte the most outspoken defender of this hybrid variety of idealism. In doing so he transformed Fichte’s I-centered approach to reality via an analysis of the conditions of knowledge/cognition and agency into an idealistic version of a monistic ontology. In this he was followed by Hegel. Whereas Fichte had mainly struggled to find an adequate expression for his activity-based conception of a self-positing I and had referred to anything outside the I only as the non-I posited by the I itself, in his early writings on the philosophy of nature Schelling tries to supplement Fichte’s approach by giving a much fuller account of nature, understood as everything that appears to be independent of us, in terms of the I-constituting activities. Because of Schelling’s elevation of nature to a central topic in his presentation of an idealistic worldview his position became characterized, although somewhat misleadingly, as “objective idealism”. On his account, we have to think of reality as an original unity (ursprüngliche Einheit) or a primordial totality (uranfängliche Ganzheit) of opposites that is internally differentiated in such a way that every particular item within reality can be seen as a partial, incomplete, or one-sided expression, manifestation, or interpretation of the most basic dynamic opposition characteristic of the whole of reality. This view of reality, which in early Schelling is quite explicitly linked to Spinoza’s one-substance ontology, obviously does not lead directly to any idealism whatsoever: one could just as well give it a naturalistic reading. In order to connect a monistic ontology to idealism, one has to somehow identify the activities at work in the constitution of the world-whole with mental or spiritual elements that are supposed to give conceptual structure to reality. This can be and was done by Schelling at different stages of his philosophical career in different ways. In the first edition (1797) of his book Ideas for a Philosophy of Nature (Ideen zu einer Philosophie der Natur), he set out to prove idealism by trying to show that “the system of Nature is at the same time the system of our mind” (IP 30; SW 1, 134). This claim is not meant to state a reciprocal relation of dependence between nature and mind and their characteristic features, i.e., according to Schelling, matter and concept, thereby presupposing that nature and mind, matter and concept nevertheless have some reality independently of each other. He rather wants us to think of nature and mind, matter and concept as being identical in the sense of being the same: the one is the other and vice versa. The reason why we as finite minds have to differentiate between them at all lies in a double perspective which is forced on us by our natural predisposition to distinguish the “outside us” from the “in us” (cf. IP 39; SW 1, 138) when looking at reality—thus Schelling sees dualism as a psychological tendency but not a philosophical option. If this disposition and its conditions were understood in the right way, we would comprehend that, as he famously writes, “Nature should be made Mind visible, Mind the invisible Nature” (IP 42; SW 1, 151) thereby making room for an idealistic conception of reality as World-Soul (On the World-Soul is also the title of a 1798 publication by Schelling.)