rational naturalism is impossible!

[Esquilax]

how can you test your cognitive abilities without using your cognitive abilities? you can't. you can't reason without using your reason. if you are unable to reason, then you are unable to determine what is true and what is false. if you're unable to do that, then everything is just as likely to be true as it is to be false and there's no way for us to determine one way or the other because that would require reason.

Wow, you are about one step away from presuppositional apologetics here, and as a consequence, one step away from making me vomit.

You can test your cognitive abilities through a number of means. For one, you can check your reasoning against the reasoning and experiences of other people. And yes, you can ask, what if everyone is suffering from the same lack of adequate cognitive processes? Well, then I appeal to evidence and the physical world. But what if the physical world is just some big illusion brought on by our lacking reasoning capacities?

Then why should I care?

As I said earlier, why should I care about any phenomena that doesn't affect me and cannot be perceived? What good does that do me? How could I possibly be justified in doing so?

The reason naturalism works is because even under the solipsistic world you're envisioning, the natural world is the only one that acts upon us. We're subject to its laws, our senses seem to correspond to its attributes, our experiences, for the most part, roughly match up. Yes, there could be a bunch of woo out there that's possible, but if it has no intrusions into the physical world then its indistinguishable from something that doesn't exist, and if its presence has even the smallest iota of effect, then it is a part of the natural world too and thus explainable in a naturalistic framework.