Reply #75: My general relativity prof

[The Traveler]

Would have been amused by the above, methinks.

A theory is not a scientific law. It is a relational collection of axioms that facilitates the generation of hypothesis. For example, Newton's three laws of motion are axiomatic expressions ... definitions or assumptions. These axioms allow one to make a hypothesis ... projectile fired out of a cannon in a vacuum will describe a parabolic trajectory, for example. We can test that and to a high degree of accuracy the results match predictions. The more good predictions that can be generated from the theoretical base, and the fewer the axioms, the better the theory.

The equation for gravitational force is the mathematical expression of a similar fundamental axiom ... Newton DEFINES a force proportional to the product of the masses divided by the square of the distance seperating them. From this one can generate a whole range of testable hypotheses. The results of these tests give one confidence that the "law" is a pretty good one.

Then someone screws things up with a couple of off the wall observations and the whole elegant structure no longer satisfies. Light bends, it turns out. Its speed appears constant regardless of motion relative to the source of light. Now to proceed further we need new axioms ...

My advisor used to hammer this into me ... there is no way to PROVE a theory correct. One can boost confidence in the value and accuracy of its predictions. But all it takes is one observation or experiment to disprove it as being "true".

As application of Newtonian mechanics gave us the means to observe and consider phenomena explained later by relativistic mechanics, so also we may expect newer theories to eventually lead us the phenomena which they cannot satisfactorily describe, and the cycle starts over again. All of which is what makes science fun.