Have you heard of the invisible man problem? The typical invisible man, as envisioned by H.G. Wells, must somehow change food into something invisible during the digestive process else the invisible man will not stay invisible. Even if he does process food into something invisible, partially digested and thus partially visible food can render the invisible man seen.
Anyhow, philosophers and men of high learning have asked the question, ‘When, oh, when does the food become invisible?’
Since the food must become invisible at some point, I’m kind of ambivalent about the question. Instead I’m more concerned about the converse. When does the invisible man’s $#!+ become visible? This question can be just as important as the standard invisible man problem. Allow the following to illustrate this:
“Roger, what’s wrong with you? You smell like $#!+, today.”
“You know, I thought I stepped in $#!+ today on my front step. But when I looked carefully at my shoes I saw that nothing was there.”
“Aren’t you one of the neighbours of the invisible man?”
“Curse him!” Roger shakes his fist in the air and looks around for the source of his wrath but of course can’t see anyone. “I was only a couple days late in returning his lawn mower. But now it’s personal! See if he ever gets his lawn mower back!”
“Uh, Roger, aren’t you trying to keep something out of reach of the greatest thief that ever lived? I mean even motion detectors don’t work on him.”