This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
When Schelling turned to the philosophy of nature in the years around 1797, he was trying to solve a problem that Kant's critical philosophy had left standing rather than answered, the sharp division between the free, self determining subject and a natural world pictured as a domain of mechanical law with no trace of freedom in it. Kant's third Critique had gestured toward organisms as a special case where mechanical explanation seemed to run out, but Schelling wanted something bolder, a philosophy of nature that treated the whole of the physical world, not just living organisms, as the visible expression of the same productive activity that shows up as freedom in a thinking subject. Nature, for Schelling, is not simply an object standing opposite the mind and studied from outside it. It is spirit, only not yet recognizing itself as such.
The technical heart of this Naturphilosophie is a claim about what an object is and what must lie beneath it. An object, Schelling argues, is always conditioned, always something determinate and bounded, and a world made up only of conditioned objects could never explain its own existence, since a chain of conditions pointing endlessly to further conditions never arrives at anything that grounds the chain. So something in nature has to be non objective in this sense, not itself a determinate thing among other things, and Schelling identifies this as the original productivity of nature itself, an activity that is always in the process of generating determinate objects without ever being exhausted by any one of them or by all of them together. Nature keeps producing because its underlying productivity can never simply coincide with, and so come to rest in, any finished product.
Schelling gives this productivity a structure rather than leaving it as an undifferentiated flow. He models it on the two poles of a magnet, opposed forces that cannot be separated from one another and yet cannot collapse into one another either, each pole existing only in tension with its opposite. This polarity repeats itself at what Schelling calls successive potentials, so that the same underlying pattern of opposition and productive tension that shows up in magnetism reappears in chemical process, in organic life, and eventually, on the highest potential, in self conscious thought. The human mind studying nature is thus not an outside observer imposing categories on inert matter, in Schelling's picture, but nature's own productivity finally becoming visible to itself, arriving at a point where it can recognize its own activity reflected back.
This is what underwrites the more evocative formula sometimes attached to Schelling's early system, that nature should be understood as visible spirit and spirit as invisible nature, two expressions of one and the same underlying activity approached from different ends. It also explains why Schelling insisted that nature could never settle into a final static order. Because its productivity is defined by never coinciding with its own products, and because that productivity is structured through persistent polar opposition rather than simple unity, nature remains restless by its very constitution, always generating new forms rather than approaching a last, complete one. Schelling would later revise, qualify, and in some respects abandon pieces of this early picture as his thought moved through transcendental idealism and toward the identity philosophy and beyond, but the basic intuition that nature and spirit are not two separate realms requiring a bridge, but one activity read in two directions, stayed with him and continued to shape how later thinkers, Hegel prominent among them, tried to hold nature and mind together within a single system rather than leaving them as Kant had, facing each other across an unclosed gap.