t only for the penal code but for the other
departments of inquiry which he intended to exhaust.[356] He had to lay
down primary truths which should be to this science what the axioms are
to mathematical sciences.[357] These truths therefore belong to the
sphere of conduct in general, and include his ethical theory.

'Nature has placed mankind' (that is his opening phrase) 'under the
governance of two sovereign masters, pain and pleasure. It is for them
alone to point out what we ought to do, as well as to determine what we
shall do.' There is the unassailable basis. It had been laid down as
unequivocally by Locke,[358] and had been embodied in the brilliant
couplets of Pope's _Essay on Man_.[359] At the head of the curious table
of universal knowledge, given in the _Chrestomathia_, we have Eudaemonics
as an all-comprehensive name of which every art is a branch.[360]
Eudaemonics, as an art, corresponds to the science 'ontology.' It covers
the whole sphere of human thought. It means knowledge in general as
related to conduct. Its first principle, again, requires no more proof
than the primary axioms of arithmetic or geometry. Once understood, it
is by the same act of the mind seen to be true. Some people, indeed, do
not see it. Bentham rather ignores than answers some of their arguments.
But his mode of treating opponents indicates his own position.
'Happiness,' it is often said, is too vague a word to be the keystone of
an ethical system; it varies from man to man: or it is 'subjective,'
and therefore gives no absolute or independent ground for morality. A
morality of 'eudaemonism' must be an 'empirical' morality, and we can
never extort from it that 'categorical imperative,' without which we
have instead of a true morality a simple system of 'expediency.' From
Bentham's point of view the criticism must be retorted. He regards
'happiness' as precisely the least equivocal of words; and 'happiness'
itself as therefore affording the one safe clue to all the intricate
problems of human conduct. The authors of the _Federalist_, for example,
had said that justice was the 'end of government.' 'Why not happiness?'
asks Bentham. 'What happiness is every man knows, because what pleasure
is, every man knows, and what pain is, every man knows. But what justice
is--this is what on every occasion is the subject-matter of
dispute.'[361] That phrase gives his view in a nutshell. Justice is the
means, not the end. That is just which prod