Interesting quote from the article ‘Physics on the Fringe’ by Margaret Wertheim:
Quantum theory and special and general relativity (which Carter, like many outsider physicists, rejects) aren’t entrenched for no reason. They seem to describe the world in a real way – having proven empirically robust and useful in various applications. Microchips, GPS satellites, and many other inventions rely on the remarkably precise predictions they make about how matter and energy interact. Wertheim points this out, but fails to adequately address the obvious question – given these theories’ successes, is it really all that much to ask that an outsider theory provide at least as much explanatory power?
Maybe the answer is an obvious, no? String theory fell into the outsider realm for a couple decades. It lacked a testable prediction (the strings are too small to be observed). General relativity had the advantage of the Sun having enough mass to bend light and an eclipse blocked the glare enough to confirm the theory valid. For it to be science, the theory must describe the way the world works better than something else. If it cannot, then maybe it belongs with metaphysics?