A biologist, a physicist, and a mathematician were sitting in a
sidewalk café when they observed two people going into an abandoned house across the
A while later they all saw three people come out and walk away.
The biologist concluded to himself, "Hmm,
those organisms must have
reproduced while they were inside
The physicist remarked to himself, "Hmm,
there must have been some
uncertainty in my first observation that made
the initial count indeterminate."
The mathematician muttered, "Now, if exactly one person enters
the house, it will be empty again."