It may be added that decisions on a point not material to the
cause are generally made without the benefit of previous argument
by counsel. The lawyers will naturally address themselves to the
controlling questions, and if well trained will see what these
are quite as clearly as the court. It is the argument at the
bar, in which different views of law are presented and each
defended by men of learning and ability, which enables the judge,
after hearing both sides and weighing all that is said in behalf
of one against all that is said in behalf of the other, to come
to the true conclusion. The Romans recognized this in their rule
as to the force of precedent in a matter of customary law. The
first thing to ask was whether "_contradicto aliquando judicio
consuetudo firmata sit_."[Footnote: "Digest," 1, 3, _de
legibus_, etc., 34.]

The retrospective effect which a refusal to follow a former
decision may have in disturbing vested rights being one of the
most cogent reasons for adhering to precedent, there is less
objection to departing from it when the decision can be so
limited as to have only a future operation. This is occasionally
feasible. Thus the High Court of Errors and Appeals of
Mississippi by an early decision held that on the dissolution of
a bank all its rights and liabilities were extinguished. Thirty
years later the Supreme Court of the same State overruled that
decision, declaring it "condemned by reason and the principles of
modern and enlightened jurisprudence," but nevertheless applied
it as a controlling precedent to a case arising out of the
dissolution of a bank which had been incorporated previously to
the time when the original decision was made.[Footnote: 1 Bank of
Mississippi _v._ Duncan, 56 Mississippi Reports, 165.]