reciprocally influence each other; and by this course of juridical
discipline they add to the readiness and sagacity of those who are
called to plead or to judge. But as human affairs and human actions are
not of a metaphysical nature, but the subject is concrete, complex, and
moral, they cannot be subjected (without exceptions which reduce it
almost to nothing) to any certain rule. Their rules with regard to
competence were many and strict, and our lawyers have mentioned it to
their reproach. "The Civilians," it has been observed, "differ in
nothing more than admitting evidence; for they reject _histriones_, &c.,
and whole tribes of people."[44] But this extreme rigor as to
competency, rejected by our law, is not found to extend to the _genus_
of evidence, but only to a particular _species_,--personal witnesses.
Indeed, after all their efforts to fix these things by positive and
inflexible maxims, the best Roman lawyers, in their best ages, were
obliged to confess that every case of evidence rather formed its own
rule than that any rule could be adapted to every case. The best
opinions, however, seem to have reduced the admissibility of witnesses
to a few heads. "For if," said Callistratus, in a passage preserved to
us in the Digest, "the testimony is free from suspicion, either on
account of the quality of the _person_, namely, that he is in a
reputable situation, or for _cause_, that is to say, that the testimony
given is not for reward nor favor nor for enmity, such a witness is
admissible." This first description goes to _competence_, between which
and _credit_ Lord Hardwicke justly says the discrimination is very nice.
The other part of the text shows their anxiety to reduce credibility
itself to a fixed rule. It proceeds, therefore,--"His Sacred Majesty,
Hadrian, issued a rescript to Vivius Varus, Lieutenant of Cilicia, to
this effect, that he who sits in judgment is the most capable of
determining what credit is to be given to witnesses." The words of the
letter of rescript are as follow:--"You ought best to know what credit