Odger's English Common Law

66 HOW TO ASCERTAIN THE LAW.
lav. " The only use of authorities or decided cases is the
establishment of some principle which the judge can follow
out in deciding the case before him. There is perhaps
nothing more important in our law than that great respect
for the authority of decided cases which is shown by our
tribunals. Were it not' for that our law would be in a most
distressing state of uncertainty." 1 The Court must decide
the case before it on the same principles as it has decided
similar cases in the past and will decide similar cases in the
future. It must act in all similar cases in accordance with
the same general rule ; else law will cease to be a science.
A legal practitioner, then, who is constantly being asked
by clients whether they shall commence or continue or defend
legal proceedings, must learn two things : firstly, how to
extract the principles of law from the decisions ; and
secondly, how to apply the appropriate principle to the facts-
of the case in which he is interested. He must weigh care-
fully each relevant case before he forms his opinion, and
elicit if possible the rule of law which governs each separate
decision. 2
It is unsafe to dwell upon an isolated passage
which seems to tell in his favour, while the rest of the
judgment does not ; it may be disastrous to his client thus
to divorce a passage from its context and apply it to dissimilar
facts. It is also unfair to the judge, whose mind
was naturally occupied with the case actually before him,
and not with any hypothetical and imaginary set of facts.
" Every judgment must be read as applicable to the particular
facts proved, or assumed to be proved, since the generality
of the expressions which may be found there are not intended
to be expositions of the whole law, but governed and qualified
by the particular facts of the case in which such expressions
are to be found." 3
This does not mean, however, that a
decision governs merely identical cases ; it is a precedent
for all cases in which the essential facts are identical. The
practitioner must ascertain what facts are essential to the
1 Per Jessel, M. E., in In re Eallett's Estate (1879), 13 Ch. D. at p. 712.
2 This is called the ratio decidendi of that case.
3 Per Lord Halsbury, L. C, in Quinn v. Leathern, [1901] A. C. at p. 506. This rule
" A judge's observation must be taken secundum materiam,"
is often thus expressed :