[Dragar]

Actually, I suppose there is another possibility, and that's that Lessans is confused by the fact that neither vision or hearing is perfect.

Perhaps Lessans is invisaging some case where the plane is heading toward us, and is so loud that we can hear it without there being sufficient light being reflected to see it.

And obvious case might be that there is some light, but not enough for our retina to register. Another case might be that the plane is incredibly loud, but so far away that the image landing on our retina occupies less than a single cell - again, our retina would be incapable of noticing such a thing. Though neither case really matches his description of "an image is being reflected towards the eye on the waves of light", although if he didn't know anything about how eyes worked, if might be something he could confusedly be trying to express. I am also a little hesitant to believe that Lessans didn't know that there were well understood reasons why we can't see things infinite far away with our prescription glasses.

Either way, in both cases this is merely a practical issue, not one of principle. A good enough telescope (or identically, a good pair of ear plugs) would once again render his example of failed.

So in this case, Lessans was foiled by nothing more than lacking a good pair of field glasses. A real tragedy.