OuterLimits wrote:Terrapin Station wrote:OuterLimits wrote:
You haven't given any . . .
For?
Oh, I get it. You're napping. That makes a lot of sense all of the sudden.
I was referring to "reasons for believing something other than just possibility".
So a meta-level justification of this. Okay. I had no idea that's what you meant.
I actually explained this earlier, although maybe I did so a bit sketchily. I'll explain it more systemically here. Take the brain in a vat scenario:
It's possible that we're just brains in vats.
It's also possible that we're not just brains in vats.
That's the case for the vast majority of claims that are possible--it's possible that P, and it's possible that not-P.
So, if we take possibility to be sufficient to warrant belief, for the vast majority of claims, we'd be required (by our adopted principle that possibility is sufficient to warrant belief) to believe both P and not-P.
Obviously, most folks are not going to be comfortable with a requirement to believe both P and not-P--that is, to believe contradictions--for the vast majority of claims. (And this is assuming that it's even really possible to believe contradictions.)
So we need something else to warrant belief in a claim. What else? Reasons for believing a claim that support the claim more than mere possibility does. Or in other words,
additional supports. Those sorts of reasons include empirical evidence that supports a claim, and logical argumentation that would support a claim. Those are two of the major epistemic justification avenues, after all--empirical evidence and logical argumentation. Those two factors wouldn't exhaust the reasons, but we do not need to exhaust reasons for a meta-level justification of needing something more than possibility to warrant belief in claims. The problem that if possibility is sufficient, we'd be required to mostly believe contradictions is enough of a justification.
Another way to look at the problem, by the way, is that logical possibility is typically defined by "not being or entailing a contradiction." So if possibility were taken as sufficient to warrant belief, we'd be required to believe mostly things that are not possible, because we'd be required to mostly believe sets of propositions that are contradictory when taken together, and contradictoriness is logical impossibility. (At least outside of paraconsistent logic.)