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In 1795 in an edition of Gilbert on evidence prepared by Capel Lofft, an English barrister," on page 301, I find an interpolation—which does not exist in the second edition published nos 1760,-entitled “Of proof by experts" as follows: "The Proof from the Attestation of Persons on their professional Knowledge, we may properly, with the French Lawyers call Proof by Experts.
"In proportion as Experience and Science advances, the uncertainty and danger from this kind of proof diminishes.
“In general it may be taken that where Testimonies of professional Men of just Estimation are affirmative, they may be safely credited; but when negative, they do not amount to a disproof of a charge otherwise established by various and independent circumstances."
This last seems to be a personal affirmation of Lofft's.
Finally Lord Ellenborough distinctly ruled upon the general question in 1807,t and that ruling will be the end for me of this historical comment, as that rule by him distinctly recognized the significance and bearing of the whole subject. The case was on a marine insurance policy, the defense being unseaworthiness. The defendant offered to call several eminent surveyors who had not seen the ship and who were to testify as to their opinion from facts in evidence. Garrow for the plaintiff objected that this was for the jury to decide from the facts, but was overruled, Lord Ellenborough saying: "As the truth of the facts stated to them was not certainly known, their opinion might not go for much; but still it was admissible evidence. The prejudice alluded to might be removed by asking them in cross examination, what they should think upon the statement of facts contended for on the other side."
There is one kind of evidence which is opinion evidence and which ran along side by side with the cases I have mentioned, i. e., testimony from a comparison of hands, or from a conclusion drawn by the witness from his knowledge of former handwriting of the person supposed to have written the paper in controversy. It does not seem to me properly to concern our subject, though it is opinion evidence. There are instances, however—and they have to-day become very common indeed—when this kind of evidence is in the strictest sense expert, that is, where a comparison of documents is made by those peculiarly skilled in the comparison of hands. I have found no case of this earlier than 1792,* where post-office clerks testified as to whether a proposed will was in a natural or forged hand, and also as to the comparison between the document in dispute and a true memorandum.
*Gilbert's "The Law of Evidence." Edition of Capel Lofft, Dublin, 1795. +Beckwith v. Sydebotham, 1 Camp. 116.
Buller, J., in sustaining the evidence, cited Folkes v. Chadd (supra) and Lord Kenyon said he remembered a case where a decipherer gave an opinion without any grounds for it, which was enough to convict and hang the defendant. This was perhaps only a sporadic and unusual case and Lord Kenyon's opinion remained doubtful thereafter. Professor J. H. Wigmore does not regard the practice as really settled until the middle of this century, and then by statute. In so far as this species of evidence is expert evidence, therefore, I think it is safe to say it hinges on what I have already tried to trace historically and is not to be connected with the rules as to handwriting or the subtleties relating to comparison of hands.
The upshot of this examination seems to be that the use of experts as witnesses existed when the present exclusive rules of evidence were not yet developed or enforced; that as the rule excluding the opinions or conclusions of witnesses took form, the use of experts being established and convenient, remained unaffected when other opinion evidence disappeared. What I have called the "exception" which expert evidence represents is therefore no more than a relic of the usage of an undeveloped age which had not so far differentiated witness from jury as rigidly to confine each to its function. The rise of expert testimony is no more than the gradual recognition of such testimony, amid the gradual definition of rules of evidence, as a permissible, because supposedly useful, archaism.
Having briefly considered the history of the present position of expert witnesses the really practical question is whether it is the best way to use the information they can give. There are two things I wish to prove: first, that logically the expert is an anomaly; second, that from the legal anomaly serious practical difficulties arise.
As to the anomaly, there is perhaps no reason to expatiate much further. The expert is in effect not telling of facts ai all, but of
•Goodtitle v. Braham, 4 T. R. 497 (1792).
uniform physical rules, natural laws or general principles which the jury must apply to the facts.*
At the expense of some formal logic I wish to try to analyze the processes involved in this whole question, because I think that the anomaly I assert can only so be proved. In our system of law the pleadings should reduce the dispute between the contestants to one or more propositions of fact, of which one side asserts the truth and which the other denies. For example let us suppose a case of slander: A complains that B said he forged a note; B says the fact is that A did forge a note. This B denies. There is only one question of fact; did A forge a note ? B seeks to prove it, A to deny it.f To prove this B will put in evidence ordinarily a number of facts from which he hopes that the jury will make the inference he wishes. For example he will bring up H to say he saw A do it, F to say he heard A admit it, E to say that he, whose name appears on it, did not sign it, and so on. A will in turn bring up X to say that H was with him and far from A at the time, Y that F was mistaken in what he heard, Z that E had possession of the note with the signature on it.
The jury must answer the proposition by taking all these facts which have so come to their knowledge and applying to them the rules drawn from their common experience. Thus they will say; H is a brother of B's, X is a stranger to A. It is well known that a man's brother is more likely to lie for him than a stranger, therefore H is more likely to be lying than X and therefore H did not see A forge the note. Again F is a young man who was near A at the time, Y is somewhat deaf and stood further away; a young man near by is more likely to hear truly than a deaf one, èrgo F heard truly what A said. So as between E and Z they will say, the mere fact of possessing a note is not in the general order of things much evidence that you signed it; at least where
*I do not think it of importance here to attempt any absolute discrimination between fact and opinion. The distinction is in practice perfectly well observed and it can serve no good purpose to deal with it at length. A comparatively slight acquaintance with formal metaphysics is enough to assure us that the apparently simplest
fact" is indeed a conclusion, involving in its affirmation an inference from certain impressions of the sense upon the assumption of a major premise, itself the creature of a past experience. At the risk of an irrelevant digression, I may say that in practice it appears to me we actually distinguish between so-called fact and opinion by merely a practical consideration, i. c., whether the inference is one which is within the fair range of dispute, or whether, given the impressions of sense, the inference from them is so self-evident as to make any attempt to question it frivolous. I call to witness here the common experience of every lawyer as to with how increasing rapidity one's questions approach the realm of "opinions" and "conclusions" as he approaches the issue in dispute. + Strictly A's
position is of course that B has not proved his proposition; this quali. fication we may disregard.
you deny you did. Lastly, they will say where one is heard to admit he forged a note and where the supposed maker denies that he signed common experience tells us it was made by the one who admits it; this is the fact with A, ergo, A forged it.
In short, the major premise, i. e., that which consists of the general rule, the jury supply from their common knowledge; the minor premise, i. e., that which supplies the particular instance whose predicate is the subject of the major, the witnesses or other evidence furnish.
Now the trouble with the expert is that he takes the jury's place and contributes the major premise. For example, suppose the issue is the same as before, but B brings on M as handwriting expert who says that whenever in two handwritings you find that the angle of inclination to the line is precisely the same, you may depend upon it, the same man wrote both. A puts on R, physician, who says that no man who has alcoholic tremor can hold a pen to write with, and that whoever has certain symptoms already in evidence as those of A, has alcoholic tremor.
What should the jury do? Having no experience in the measurement of angles in handwritings and, as we may hope, no extended experience in alcoholic tremor and its effects and symptoms, they should take those generalizations into the stock of major premises which they apply to the facts, and using them, say whether A wrote the note or did not. Thus if they believe M, then after measuring the angles in the note and in, say, the signature to the verification of the pleadings, if the angles are alike, they would conclude that the same hand wrote both; the angles are alike, ergo the same hand wrote both. Or, with such symptoms A could not even hold a pen, he had such symptoms, ergo he could not hold a pen, much less write.
Now the important thing and the only important thing to notice is that the expert has taken the jury's place if they believe him.* It is of course not necessary for the jury to accept the expert's opinion, but were it not really of possible weight with them, it would not be relevant, and if of possible weight, it is only because
•It can hardly be necessary to say that as to the credibility of any witness there always must remain a questinn for the jury alone. They have to determine in each case the fractional co-efficient of verity, to borrow from mechanics, and multiply the statements made before them by that fraction, before they can judge. Moreover in getting the personal equation of each witness, they shall use common sense or the general inferences of men under the circumstances, and will not be helped by any expert knowledge, at least only in rare cases, e. 8., insanity or the malingering of insanity.
it furnishes to them general propositions which it is ordinarily their function and theirs only to furnish to the conclusion which constitutes the verdict.
So much therefore for the anomalous position of the expert witness. Whether it works any practical evil or not is a very different matter. There can be, in my opinion, no legal anomaly which does not work evil, because forming an illogical precedent, it becomes the mother of other anomalies and breeds chaos in theory and finally litigation. No doubt in our law under the supposed garb of equity and justice much is constantly done no less anomalous, and I confess that to say of a thing in our law to-day that it is an anomaly is unfortunately to give it hardly any stigma, it a supposed immediate advantage is to be found from its existence. That the present position is not satisfactory to anyone will I believe be admitted. True it is that some are found hardy enough to support it,* but there are not many, and the criticism comes with great unanimity. I shall therefore try to point out the practical defects, as I believe necessarily inherent in the present system, hoping thereby to obtain a readier hearing than for any purely legal or logical difficulties.
The serious objections are, first, that the expert becomes a hired champion of one side, second, that he is the subject of examination and cross-examination and of contradiction by other experts.
Enough has been said elsewhere as to the natural bias of one called in such matters to represent a single side and liberally paid to defend it. Human nature is too weak for that; I can only appeal to my learned brethren of the long robe to answer candidly how often they look impartially at the law of a case they have become thoroughly interested in, and what kind of experts they think they would make, as to foreign law, in their own cases.
The main difficulty, the fatal difficulty, is, however, still further to seek and lies in the logical fulfillment of the expert's position, as witness and not as adviser of the jury. The result is that the ordinary means successful to aid the jury in getting at the facts, aid instead of that in confusing them.
In the trial of an action or suit each party produces his witnesses and brings out from each witness certain facts the witness has observed. So far so good. The jury is in possession of any number of facts you will, all supposedly relevant to the inquiry
. *See William L. Foster, ir Harv. L. Rev. p. 169.