 Notice that PEW addresses justification rather than knowledge. On the reasonable assumption that knowledge requires justification,  (4)  implies that our perceptual beliefs do not count as knowledge. One who denies this assumption could easily rewrite PEW in terms of knowledge rather than justification with little or no reduction in plausibility. I have reconstructed PEW in a way that is supposed to be intuitively compelling. Were we to get specific about the implicit quantification involved (we have no good reason for thinking that any perceptual appearances are veridical? that perceptual appearances are in general veridical? that this perceptual appearance is veridical?), the argument would get a lot more complicated. The simpler version presented above is sufficient for our current purposes.