Darrigol in Electrodynamics from Ampere to Einstein writes:
In Germany, a few marginal followers of Schellings Naturphilosophie criticised the general notion of fluids acting at a distance and sought a deeper unity of nature that would relate apparently disconnected phenomena. They favoured a dynamistic, anti-Newtonian view of physical interactions in which matter and force was not distinguished. Matter was only a balance of two opposing forces and every action at a distance was to be reduced to a propagating disturbance or polarity of this balance.
This appears to be clearly related to speculations by William Clifford on space and matter. For example, in a paper read out to the Cambridge Philsophical Society in 1870 he said:
That small portions of space are in fact of a nature analogous to little hills on a surface which is on the average flat; namely, that the ordinary laws of geometry are not valid in them.
That this property of being curved or distorted is continually being passed from one portion of space to another after the manner of a wave.
That this variation of the curvature of space is what really happens in that phenomenon which we call the motion of matter, whether ponderable or etherial.
That in the physical world nothing else takes place but this variation, subject (possibly) to the law of continuity.”
The resemblence here is quite clear as is the resemblence to GR. There are also some speculations by Newton where he pondered the ponderability of atoms and suggested that they were merely the balance of forces.
Its generally taken that Mach had a large influence on Einstein, on his own admittance. However there is a clear resemblence between what these followers of Schelling argued for and that of the theory of gravity put forward by Einstein, that one might argue for an indirect or direct influence. Was there? And if so, why has this particular tradition been down-played in the history and philosophy of physics?
According to Keith Richardson on a discussion of Schellings philosophy
[His] early philosophy of nature met opposition in part because its ethical and political interests—not just its allegedly wild and “unverifiable” analogizing—were thought to have invalidated its “scientific” claims.
If this is the case, what were specifically Schellings ethical & political interests that caused his philosophy to become neglected?