How will we know a true T.O.E. when we see it?

[mrspeedybob]

Suppose we start with some observed phenomena A. We explain A in terms of B, C, and D which we consider more basic. When asked to explain B we do it in terms of other things we consider even more basic until we reach a point where there is nothing we can explain a given phenomena in terms of. For example...

Why does water evaporate when heated?

Heat is average kinetic energy of molecules. If a molecule has enough kinetic energy to overcome gravity and electrostatic attraction to the other water molecules it will leave the mass of water and fly freely about in the air.

Now we have the problem of explaining kinetic energy, gravity , and electrostatic attraction.

At some point we will either be talking in terms of phenomena that cannot be explained in terms of anything more basic because there is nothing more basic or we will simply not know what it is that is more basic.

How will we know the difference between a truly fundamental phenomena and one which we simply cannot explain yet? I understand that G.R. and Q.M. are at odds with one another and so 1 or both must be in error and so we know that there is something more fundamental then the understanding we now have but once we find a self consistent theory how will we know if we are done and know everything there is to know about physics or if there is some deeper explanation for why things are the way they are?

 

[Nabeshin]

How will we know the difference between a truly fundamental phenomena and one which we simply cannot explain yet?

We cannot. I suppose, we could consider something truly fundamental when all the people who understand it are completely satisfied with the theory. Theories such as QM and GR leave something to be desired, in many arenas, and so people get an inkling, experimental evidence aside, that they may not be the whole story.

But once you get down to it, your physics has to be axiomatic. That is, there have to be a set of assumptions from which you derive all the physical laws. The goal of constantly refining our theories is to ultimately reduce the number of axioms necessary to describe all known phenomenon. (Note, I'm not particularly willing to get into the logic of all this, godel's incompleteness theorem and whatnot. Others can if they find it relevant)