TOP-DOWN vs. BOTTOM-UP

27 Jan TOP-DOWN vs. BOTTOM-UP

Most physicists today are Einsteinian “top-downers”. They regard the various relativistic effects as consequences of the Principle of Relativity and that’s the way they present relativity to the public. They believe that deriving these effects as consequences of the way fields behave is somehow illegitimate.

“Look what you’ve done to our beautiful theory,” they say. “You’ve reduced it to mere physical effects. The F-L contraction is not a physical process that occurs because field configurations are affected by motion; it is something that is built into the nature of space. And this time dilation – it’s not that processes happen more slowly, it is a property of time itself.”

While the above is my paraphrasing, note how Einstein’s biographer, Abraham Pais, applied the condescending word “corrected” to the bottom-up explanations given by FitzGerald and Lorentz:

FitzGerald and Lorentz had already seen that the explanation of the Michelson-Morley experiment demanded the introduction of a new postulate, the contraction hypothesis. Their belief that this contraction is a dynamic effect (molecular forces in a rod in uniform motion differ from the forces in a rod at rest) was corrected by Einstein; the contraction of rods is a necessary consequence of his two postulates and is for the first time given its proper observational meaning in the June paper.

The fact is, either approach is correct and one does not preclude the other. Yes, the Principle of Relativity is elegant and the top-down approach is easier to use; physicists love it for that reason. But the field equations are also elegant and they not only contain the Principle of Relativity within them, they also provide a physical explanation for effects that otherwise are paradoxical. We can never know if God started with the Principle of Relativity and derived the field equations or started with the field equations from which follows the Principle. If She started with the principle that the laws of nature should be the same in all moving systems, then She also provided mechanisms to make it happen. And if the mechanisms are there, why not use them? They are real and understandable, and they should not be ignored.