Animals appear in Heraclitus' fragments
on a number of occasions. As I see it, Heraclitus uses them for two
main purposes.
He compares men who chase after pleasure
to brute beasts.
Humans are different than animals.
Humans have a rational soul, and this connects them with the fiery λόγος.
Men who chase after pleasure as the highest good are no better than animals.
Pleasure destroys the rational part of the soul, seen clearly by intoxicated
humans. These foolish people did not recognize the structure of the
world; thus, they do not how to live in the world.
He contrasts the way things seem
to us with the way things seem to animals.
Evidence for the harmony of opposites
comes from animals. Things have different properties when viewed
by animals and humans. "A horse, a dog and a human being have different
pleasures; asses prefer straw to gold" (B9).
Heraclitus uses this to prove that in particular objects (like salt-water),
both opposites exist in a harmony (like pure
and impure B61).
