If our faculties are unreliable under naturalism, they’re unreliable for evaluating Plantinga’s argument too. Doesn’t the argument saw off the branch it sits on?

This is a common reply, and Plantinga has an answer: the argument is a reductio. It assumes naturalism for the sake of argument, derives that the naturalist has a defeater for all their beliefs, and concludes that naturalism cannot be rationally held. The theist who runs the argument does not accept its premise and so does not inherit the defeater. Whether the reductio structure succeeds is debated, but the branch-sawing charge misreads the form of the argument.