With all their enormous differences in natural endowment, men agree in
one thing, and that is their innate desire to enjoy the pleasures and
escape the pains of life; and, in short, to do nothing but that which
it pleases them to do, without the least reference to the welfare of the
society into which they are born. That is their inheritance (the reality
at the bottom of the doctrine of original sin) from the long series of
ancestors, human and semi-human and brutal, in whom the strength of this
innate tendency to self-assertion was the condition of victory in the
struggle for existence. That is the reason of the _aviditas vitae_--the
insatiable hunger for enjoyment--of all mankind, which is one of the
essential conditions of success in the war with the state of nature
outside; and yet the sure agent of the destruction of society if allowed
free play within.