It is therefore clear that the criteria of relevant resemblances
and differences may often vary with the fundamental moral
outlook of a given person or society. Where this is so, assessments
of the justice or injustice of the law may be met with
counter-assertions inspired by a different morality. But sometimes
a consideration of the object which the law in question
is admittedly designed to realize may make clear the resemblances
and differences which a just law should recognize and
they may then be scarcely open to dispute. If a law provides
for the relief of poverty then the requirement of the principle
that 'Like cases be treated alike' would surely involve attention
to the need of different claimants for relie£ A similar criterion
of need is implicitly recognized when the burden of taxation
is adjusted by a graded income tax to the wealth of the individuals
taxed. Sometimes what is relevant are the capacities
of persons for a specific function with which the exercise of
the law in question may be concerned. Laws which exclude
from the franchise, or withhold the power to make wills or
contracts from children, or the insane, are regarded as just
because such persons lack the capacity, which sane adults are
presumed to have, to make a rational use of these facilities.
Such discriminations are made on grounds which are obviously
relevant, whereas discriminations in these matters
between the sexes or between persons of different colour are
not; though of course it has been argued in defence of the
subjection of women, or coloured people, that women or
coloured people lack the white male's capacity for rational
thought and decision. To argue thus is of course to admit
that equal capacity for a particular function is the criterion of
justice in the case of such law, though in the absence of any
evidence that such capacity is lacking in women or coloured
persons, again only lip-service is paid to this principle.