First, however, let us see, Captain, if we agree on some fundamental points.

How do we detect the existence of life?
Is it not by _movement_?
Is not _motion_ its result, no matter what may be its organization ?" "Well," said the Captain in a drawling way, "I guess we may grant that." "Then, dear friends," resumed Barbican, "I must remind you that, though we have had the privilege of observing the lunar continents at a distance of not more than one-third of a mile, we have never yet caught sight of the first thing moving on her surface.

The presence of humanity, even of the lowest type, would have revealed itself in some form or other, by boundaries, by buildings, even by ruins.

Now what _have_ we seen?
Everywhere and always, the geological works of _nature_; nowhere and never, the orderly labors of _man_.

Therefore, if any representatives of animal life exist in the Moon, they must have taken refuge in those bottomless abysses where our eyes were unable to track them.