Most every knows that Descartes said matter was pure extension. It's not well known though that pure extension for him, meant "motion and rest" (as it did for his follower Spinoza). Basically an "extension" is an object composed of force. Extension is force.. Force limits itself to a state of rest unless struck by another object. Collision gives parts of one a body to another. When something is in motion it will continue to accelerate forever (unless checked) because force is infinite in each body. This was the start of science in the modern age. But Descartes's specific laws of motion were contradictory, however, and made little sense (although the Cartesians were fascinating). Still, this move away from viewing matter in the common sense way has in modern times also come to the front of the conversation. There is "information theory" and as well as Whitehead's 'event" ontology. To my mind the latter strays even further away from a materialist stance than information theory does and gets close to idealism. Now so far all this has to do with philosophy. Physics it about prediction. When we come to straight physics though, we have the situation given us by Einstein and general relativity. If time and space are relative, and not only that, but the size of your very body is relative, it seems to me we have to continue to try to understand what matter even is.

Nonetheless will this route lead us further and further from common sense, or could it bring us back full circle? Could things be so relative that they become absolute (1.)? Anyway, Wittgenstein said "The sense of the world must lie outside the world." I hope he is wrong

1.) or is everything so absolute that it becomes relative