[grey_whiskers]

You might also want to add the correspondance principle. The Correspondance Principle says, "Any new theory must contain the old theory as a limiting case." The reason for the incluison is that some folks think that theories can be replaced and the old one junked. That's never true. The old theory must always appear as a limiting case.

One other note, might want to have the addendum that the old theory should be (at least somewhat) empirically validated: e.g. the law of gravitation vs. Aristotle's de Caelo; phlogiston vs. oxygen. The existence of phlogiston was a widely held [belief? theory? -- people weren't using empiricism as much back then, which was part of the problem :-) ]. Call it a theory. Nonetheless, it was discarded in favor of valence chemistry. Or another example would be Geocentric cosmology (epicycles, etc.). To a certain extent they could correctly predict planetary movements, but at the cost of a lot of trouble. But the theory was completely supplanted by Copernicus etc.

Cheers!

[spunkets]

"The existence of phlogiston was a widely held [belief? theory? -- people weren't using empiricism as much back then, which was part of the problem :-) ].Call it a theory. Nonetheless, it was discarded in favor of valence chemistry."

It was an unproven hypothesis. The correspondance principle only applies to theories based on a solid fundation of real evidence. W/o empirical evidence, there is no theory.