[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.

[grey_whiskers]

W/o empirical evidence, there is no theory.

Grey area due to semantics, there were cases in which it "appeared" to work; and the principles of empiricism were not firmly enough established that people back realized it was an unproven hypothesis. The distinction between hypothesis and theory wasn't as firm back then. One of the drawbacks of scholasticism. (See also Galen...; or some analogy to Owen Barfield's "ancient unities"...)

Cheers!