In certain cases, indeed, the resemblances and differences
between human beings which are relevant for the criticism of
legal arrangements as just or unjust are quite obvious. This
is pre-eminently the case when we are concerned not witl:t the
justice or injustice of the law but of its application in particular
cases. For here the relevant resemblances and differences
between individuals, to which the person who administers
the law must attend, are determined by the law itself. To say
that the law against murder is justly applied is to say that it
is impartially applied to all those and only those who are
alike in having done what the law forbids; no prejudice or
interest has deflected the administrator from treating them
'equally'. Consistently with this the procedural standards such
as 'audi alteram partem' 'let no one be a judge in his own cause'
are thought of as requirements of justice, and in England and
America are often referred to as principles of Natural Justice.
This is so because they are guarantees of impartiality or
objectivity, designed to secure that the law is applied to all
those and only to those who are alike in the relevant respect
marked out by the law itself.