Homo Sapiens, n. [Lat. man the knowing] The scientific name for man.

Common men seem to have no difficulty deciding, "Is that entity over
there a man or a beast?"

To scientists and philosophers, though, it is not such a
straightforward question. They are in pursuit of the one action which
sets apart man from the beasts.

Some value technology, measuring the progress of a civilization's
culture, morality, and character by the machines it produces. Thus,
the distinguishing feature between man and beast is the ability to use
tools. But even some birds use twigs in order to get food.

Now, language seems to be the prime locus of attention. The
distinguishing feature is the use of words, that is symbols, to
communicate. But dolphins do that. So it's really the ability to put
words or symbols together in new grammatical combinations -- or at
least was, until it was discovered that a chimpanzee can do that, too.

This present lexicographer is unaware of any beasts which consider it
necessary to spend time arguing about what it is that sets them apart
from other species, let alone understand doing and being, accident and
substance, well enough to confuse them.

-- Hayward's Unabridged Dictionary