1. A good case can be made that externalist theories of justification (or warrant) are undercut by evolutionary naturalism in that with the conjunction of the two we have a defeater for our belief in the reliability of our cognitive faculties (i.e., that part of our noetic structure responsible for producing true beliefs).
2. A good case can be made that internalist theories of justification (or warrant) imply (or are assumed by) substance dualism in that these theories seem to be motivated by first-person perspectives of the knowing and experiencing subjects, they seem to assume a same-self as the one having access to and being aware of the justifying reasons for belief, and they seem to imply some other features which are problematic for evolutionary naturalism: At least on some readings, libertarian free-will is assumed due to the ought-implies-can principle implicit in deontologism, and most analysis of internalist theories of justification and warrant attach justification (or warrant) to beliefs which, on some naturalist theories, are queer entities that need to be eliminated, and also requiring a normativity condition at odds with descriptive accounts of the world evolutionary naturalists must give, and lastly doxastic voluntarism seems to be implied by internalists - this seems to be at odds with the pictire of the world that naturalists give us. Indeed, this is why many naturalists hold to an externalist theory of knowledge, calling it "naturalized epistemology." It should be granted that subtance dualism is incompatible with evolutionary naturalism.
3. Externalist and internalist models seem to cover the field of possible ways justification or warrant is conferred on beliefs (or C-fibers firing!).
4. Therefore, a good case can be made that evolutionary naturalism undercuts the only possible ways justification or warrant can be conferred on beliefs.
Premise 1 is supported by arguments like Plantinga's EAAN. Premise 2 is supported by arguments like Reppert's AFR.