We can always try to dig deeper into the mechanism of phenomena. Einstein
improved greatly upon Newton's theory of gravitation by explaining it in terms of
space-time curvature. Of course there are still many implications of this explanation
which have to be more thoroughly tested, such as gravitational waves. (BTW, we do have
indirect evidence that these carry energy away from a system as Einstein's theory
predicts.) But you can also ask about the "why" of the mechanism. Why is the geometry
of space-time that of Riemann instead of something more general? (Or is it perhaps
really more general with, e.g., torsion as well as curvature?) Why are there 4
dimensions of space-time - or are there perhaps more, as current revivals of some old
unified field theories argue? Is space-time really built up from strings?
Analogy: A puerly phenomenological approach to driving a car is content if it
works, without looking under the hood. A good mechanic knows much more about what's
under the hood &c - without necessarily knowing how to solve Newton's equations, the
physics & chemistry of combustion, &c. & an engineer who knows the physics &
chemistry of combustion may not know much about the quantum theory underlying those
phenomena. There are different levels of understanding of mechanism.
George
George L. Murphy
gmurphy@raex.com
http://web.raex.com/~gmurphy/