Berkeley's argument for the existence of God

[FatAndFaithless]

@F&F So heat itself would be an idea to Berkeley. He never contradict John Locke or David Hume on this (both considered HEAT to be a "secondary quality" of the fire--- ie it is a perceptive phenomenon... not a real thing. Berkeley IS an empiricist in that regard (no different than Locke or Hume). He just goes one step further and says the whole damn fire is an idea... which is all we ever perceive it as.

PS: I have plenty of refutations for Berkeley, but I kind of like him so I'm doing devil's advocate duty here...

Heat is not a perception though.  We know about energy transfer, the movement of atoms, the chemical reaction of burning something, etc.  It's an extant thing that would exist whether or not we were here to perceive it.  And how would one empirically prove that nothing exists materially, if all the empirical evidence is, apparently, simply a perception or an idea? How can he call himself an empiricist if he simultaneously says that all experience (evidence, data, etc) is simply perception?

I just fail to find any use at all in going down this rabbit hole.  It doesn't help us understand anything better (especially considering how much more we know about neuroscience, physics, etc now).