PHAEDO - I do not know how we can tell which is superior. The primordial
cell in differentiating out of homogeneity into heterogeneity developed
different qualities in different beings, and of the organs integrated
from the heterogeneous elements each has its use and many are essential
to life. In man the brain is more powerful than in the ox, but in the ox
the stomach is more powerful than the brain, and while both stomach and
brain are necessary, yet is one with a weak brain and strong stomach
doubtless happier than one with a weak stomach and strong brain. Is it
not, then, true that the stomach is nobler than the brain, and if so,
then the pig and the lion and the goat, which have strong stomachs,
nobler than man, whose stomach could in nowise digest carrion, or
alfalfa, or tin cans, and therefore may it not be that the earth was
made for the lower animals, who can use more of its products than man?

SOCRATES - That is a deep thought, O Phaedo, which shows that you are
well up in your Spencer, although shy in your surgery, for it is true
that the stomach has been removed from a man who lived happy ever after,
while neither man nor beast ever lived a minute after his brains were
knocked out; but, is it not true that it is by the function of the brain
that man makes his powers more effective than those of animals stronger
than he, so that he is able to bear rule over all the lower animals and
either exterminate them from the earth or make them to serve him?

PHAEDO - Yes, that is true.

SOCRATES - And we cannot say that the earth was made for beasts which
themselves are made to serve the purpose of man, for as plants are
consumed by beasts, so beasts are consumed by man who acquires for his
own use and enjoyment whatever power is generated by the organs of all
other living things.