Philosophical principles, much like scientific laws, are descriptive, not prescriptive. But where scientific laws are subject to testing, refinement, and falsification, philosophical principles have no objective and effective winnowing process. The law that heavier objects fell faster than lighter ones gave way to Vf= a t^2 ; Newton’s law of universal gravitation gave way to spacetime; a deterministic, mechanistic cosmos gave way to a probabilistic, intuition-shattering sea of information. What objective tests, then, beyond logical consistency, do we have for our philosophical presuppositions about the absolute, ultimate nature of reality?
And to then use those presupposed principles to prove new presuppostions, seems, well, preposterously presumptuous .
(Sorry, I couldn’t resist)
In terms of theist apologetics, this is pretty much what all such conversations sound like to me.
“How do you know that the claim you’re presupposing, that everything requires a cause, is true?”
“Our presupposition is supported by a metaphysical principle, the Principle of Sufficient Reason. It is a principle which says that everything must have a cause.
“You’re supporting your presupposition with the same presupposition, but now you’re calling it a metaphysical principle?’
“That’s about the shape of it, yep. ”