§ 176 Criticism of the Law of Evidence
We have in a former chapter considered the advantages and disadvantages of that substitution of predetermined principles for judicial discretion which constitutes the essential feature of the administration of justice according to law. In no portion of our legal system is this question of more immediate importance than in the law of evidence. Here, if anywhere, the demerits of law are at a maximum, and those of the opposing system at a minimum. General rules for the predetermination of probative force are of necessity more or less false. It is impossible to say with truth and a priori what evidence is or is not sufficient for proof. It is not true that hearsay is absolutely destitute of evidential value; it is not true that a contract for the sale of land cannot be satisfactorily proved by oral testimony; it is not true that the contents of a document cannot be well proved by a copy of it. To elevate these maxims and such as these from their proper position as counsels for warning and guidance, to the level of rigid and peremptory rules, is to be inevitably led astray by them. Like all general principles they are obtained by way of abstraction and elimination of elements which may be, in particular instances, of the first importance. To apply such abstract principles to concrete cases without making the needful allowance for the special circumstances of these cases is as wise as to apply the laws of motion without allowing for the disturbing influence of friction.
No unprejudiced observer can be blind to the excessive credit and importance attached in judicial procedure to the minutiae of the law of evidence. This is one of the last refuges of legal formalism. Nowhere is the contrast more striking between the law’s confidence in itself and its distrust of the judicial intelligence. The fault is to be remedied not by the abolition of all rules for the measurement of evidential value, but by their reduction from the position of rigid and peremptory to that of flexible and conditional rules.480 Most of them have their source in good sense and practical experience, and they are profitable for the guidance of individual discretion, though mischievous as substitutes for it. The cases are few in which we can rightly place such rules upon the higher level. In general, courts of justice should be allowed full liberty to reject as irrelevant, superfluous, or vexatious, whatever evidence they will, and to accept at such valuation as they please whatever evidence seems good to them. We must learn to think less highly of the wisdom of the law, and less meanly of the understanding and honour of its administrators, and we may anticipate with confidence that in this department at least of judicial practice the change will be in the interests of truth and justice.