diately at the highest point. The wisest thus leaning to a diminution, and the least wise to an augmentation, of their respective influence on the judge, the scale might produce an effect contrary to what the author expects from it. It appears to me, that in judicial matters, the true security depends on the degree in which the judges are acquainted with the nature of evidence, the appreciation of testimony, and the different degrees of proving power. These principles put a balance into their hands, in which witnesses can be weighed much more accurately than if they were allowed to assign their own value, and even if the scale of the degrees of belief were adopted, it would still be necessary to leave judges the power of appreciating the intelligence and morality of the witnesses, in order to estimate the confidence due to the numerical point of belief at which they have placed their testimony."

§ 73. The mathematical calculus of probabilities, or Application of "Doctrine of Chances," has, as is well known, been the calculus of probabilities to found of essential service in various political and social judicial testimatters, apparently unconnected with the exact sciences. mony. The modern system of Life Insurance, in particular, owes almost its existence to that branch of mathematics. Among other things, the notion of applying the calculus of probabilities to estimating the value of testimony given in courts of justice presented itself (y),—an object sought to be accomplished, by adapting the well established formula which express the probability of concurrent events, to the probability of the evidence of concurring witnesses or independent facts. But no real

(y) Laplace, Essai Philosophique sur les Probabilités, Paris, 1819; Lacroix, Traité Elémentaire du Calcul des Probabilités, Paris, 1833; Poisson, "Recherches sur la Probabilité des

Jugemens en matière civile et en
matière criminelle," &c., Paris,
1837;
and the article "Proba-
bility" in the Encyclopædia Bri-
tannica.

analogy exists in this respect between judicial testimony and life insurance or other matters of a similar nature. In the latter a series of facts and figures, collected by long and accurate observation, and carefully registered, supply data that effectually bring the subject within the range of mathematical analysis, a condition which wholly fails when we attempt to deal practically with the former (z). Still even here the calculus of probabi

&c., the probability of their concurrence will be expressed by this formula—

(m) (mm) (m)

&c.

m+n, When the total number of possible cases, and their ratio to the number of favourable chances, are unknown, still approximate values of the probabilities of events can be obtained, by having recourse to hypotheses framed according to the results of a certain number of trials or observed events. In such cases the probability of a fresh simple event is obtained by calculating, according to the events already observed, the probability of the different possible hypotheses, and taking the sum of the products of these probabilities by those of the event, calculated according to each hypothesis. The calculus of probabilities has been applied to the subject of human testimony, by supposing that, in a certain number of depositions, say m+n, a witness has told truth in m cases, and falsehood in n cases; although,

lities is not without its use. "La plupart de nos jugemens," says one of the most distinguished writers upon it (a), "étant fondés sur la probabilité des témoignages, il est bien important de la soumettre au calcul. La chose, il est vrai, devient souvent impossible, par la difficulté d'apprécier la véracité des témoins, et par le grand nombre des circonstances dont les faits qu'ils at

veracity of each to be the same,
weshall have m=m'n=n', &c., and
the expressions last obtained will
become
and
If
mp+np mP+np
instead of witnesses we have
circumstances, the probability of
any fact, as, for instance, the
guilt or innocence of an accused
person, is calculated in the same
way, and will be the compound
proportion of the simple probabi-
lities arising from each of those
circumstances; though in esti-
mating strictly the probability of
guilt resulting from each circum-
stance, the probability of the
truth or falsehood of the wit-
nesses deposing to that circum-
stance must be taken into the
account.

For the deduction of the above formulæ, see the works cited in the last note. The most cursory inspection of these expressions will shew how impossible it would be for the practical purposes of justice to assign even approximate values to the quantities m and n, to say nothing of the other probabilities necessary to be computed.

(a) Laplace, ut supra, p. 135.

2. Double principle of decision.

testent, sont accompagnés. Mais on peut dans plusieurs cas résoudre des problèmes qui ont beaucoup d'analogie avec les questions qu'on se propose, et dont les solutions peuvent être regardées comme des approximations propres à nous guider, et à nous garantir des erreurs et des dangers auxquels de mauvais raisonnemens nous exposent. Une approximation de ce genre, lorsqu'elle est bien conduite, est toujours préférable aux raisonnemens les plus spécieux." Approved authors in our own law have accordingly availed themselves of the calculus of probabilities, as applied to hypothetical states of facts, to illustrate the value of different kinds of evidence (b).

§ 74. The remaining abuse, if less monstrous than the other (c), is to the full as formidable; and is sure to be found wherever the rules of evidence are too technical or artificial, and the decision of questions of fact is entrusted to a judge, instead of a jury or other casual tribunal. Although no tribunal could venture systematically to disregard a rule of evidence, however absurd or mischievous-this would be setting aside the lawtribunals may occasionally suspend the operation of such a rule without risk, and even with applause, when its enforcement would shock common sense; and the upright man who has the misfortune to be judge under such a system, either relaxes the rule in those cases, or carries it out at all hazards under all circumstances. The unjust judge, on the contrary, converts this very strictness of the law into an engine of despotism, by which he is enabled to administer expletive or attributive justice at pleasure; while the world at large sees nothing but the promulgated system, little suspecting that there is in the back ground an esoteric one with which only

(b) See further on this subject, infrà, Part 3, book 2, ch 1,

sect. 1.

(c) See § 69, et seq.

the initiated are acquainted. When a rule of this kind militates against an obnoxious party, the judge declares that he is bound to administer the law as he finds it, that it is not for him to overturn the decisions of his predecessors, or sit in judgment on the wisdom of the legislature and to blame him for this is impossible. But is the party against whom the rule presses a favoured one-the judge discovers that laws were made for the benefit of men, not their ruin, that technical objections argue a rotten cause, and that the first duty of every tribunal is to administer substantial justice at any price. The badness of the rule is so obvious that it would be difficult to find fault with this either: and by thus shifting the urn from which the principle of his decision is taken, the judge sits, like the fabled Jove (d), the absolute arbiter of almost every case that comes before him (e).

§ 75. We have thus endeavoured to explain the prin- Conclusion. ciples on which judicial evidence is founded, to demonstrate its utility and necessity, and point out the abuses to which it is most liable. The peculiar system existing in any particular place will of course depend much on the substantive municipal law to which it is attached,