- #141
GeorgeDishman
- 419
- 29
steve watson said:My problem is with the nature of "space" and what it is or rather what it is not. Nobody seems to be able to give me a straight answer. But everyone seems to think "space" is a "thing" rather than "nothing". If "space" were "nothing" wouldn't that turn a lot of these theories upside down?
It's not a trivial question. For example, if space is the absence of anything, how can it have a permitivity and permeability? What about the Casimir Effect, is that caused by "stuff in space" or is it a property of the vacuum itself? Space may not be a "thing" but it definitely seems to have measurable properties. You might also like to do a search for the term "substantivalism" (be careful with the spelling) and look at the Hole Argument just to get a flavour of this topic:
http://plato.stanford.edu/entries/spacetime-holearg/
Note that the Hole Argument is a problem for manifold substantivalism but perhaps not for metric substantivalism (which the SEP barely mentions).
You should also consider what gravitational waves (as indirectly measured by Hulse and Taylor) and "gravitational wave recoil" imply for the existence of the metric.
http://www.black-holes.org/explore2.html