In 1870, Clifford, the English mathematician and sometime philosopher wrote the following in his book, On the Space theory of Matter;
I hold as a fact:
That small portions of space are in fact of a nature analogous to hills on surface, on 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 on from one portion of space to another after the manner of a wave.
That this variation in the curvature of space is what is really what happens in that phenomena we call motion of matter.
That in the physical world nothing takes place except this variation, subject (possibly) to the law of continuity.
This is astonishingly like Einsteinfs GR, it is also in this description astonishingly like Thales description of the world as water.
What were the philosophical influences that led Clifford to this conjecture half a century before Einstein found a complete solution to this conjecture in the form traditionally favoured by physicists of the modern era - physical mathematics ie calculus?
Its possibly worth noting in this regard, that Aristotles Physics VI.1 on Continuity, states that:
distance, time and movement are all continua.
Notably, to place these three very distinct phenomena into one genus makes them commensurable; and also, continua for Aristotle are the bearers of change, alteration and variation ie waves: they change in one direction say increase, until increase is no longer possible - rest - and then decrease.
The obvious place to look is in Clifford's book or/and his bibliography - but I don't have access to a copy.