Expert testimony

“ The usual effect of the expert testimony on one side is to neutralize that on the other, for there is no practical way for the jury to distinguish between experts, since the foolish ones generally look as learned as the wise ones. ”

“ While the Court, or Judge, determines the competency of the witness to testify as an expert, the weight to be accorded to his testimony is for the jury to decide. The testimony of an expert is to be weighed and tested like any other kind of evidence, and is to receive just such credit as the jury may think it entitled to. ”

“ The first test that the court should apply to determine whether expert testimony is admissible in any event, is, whether the facts relevant to the issues are such that they can be introduced into evidence, and whether the jury are competent to draw a reasonable inference therefrom—not necessarily the inference that the court would draw, or that I would draw, or that the expert would draw; and are they competent to draw a reasonable inference of their own. ”

“ There are also some matters of fact which apparently transcend the dividing line between common experience and judgment and scientific experience and judgment, as to which expert testimony is not receivable, but the jury and court must weigh the facts and draw the inferences for themselves. ”

“ In reality the testimony of expert witnesses is very good evidence. If it is given in plain and understandable English and the jury think the expert a clean-cut, sensible man, it is just what the jury want to learn. ”

“ It is too true that very frequently persons have been allowed to give testimony as experts who were utterly without experience in any calling that tends to bestow the proper qualifications for giving expert testimony. ”

“ In regard to the objection that these witnesses were not qualified as experts, in addition to the fact that three of them were on board of the tug at the time, and in its service, the court charged the jury that the value of expert testimony depended very largely upon the skill, the information or the knowledge, and the experience of the witness; and that, in giving weight to the expert testimony, the jury should be careful to ascertain what the evidence established as to the truth of the bypo hetical questions put to the witnesses by the counsel on the one side and on the other. ”

“ Where the defense presents expert testimony concerning the accused's mental condition, a Government expert, testifying in rebuttal, may testify as to his conclusions concerning the accused's mental responsibility or capacity based on interviews with the accused conducted without advising him of the foregoing rights. ”

“ They should control only as they are found to be reasonable.' In short, as stated by a recent writer upon Expert Testimony, the ultimate weight to be given to the testimony of experts is a question to be determined by the jury ”

“ When expert testimony was first introduced it was received with marked respect. The expert witness was counted as a professor in his specialty, and his word was almost final. Experience, however, has materially altered all this. The field from which the expert may be cited has been vastly broadened, whilst at the same time his testimony is accepted with much more caution, and less credence. ”

“ The whole effect of the testimony of an expert witness may sometimes effectually be destroyed by putting the witness to some unexpected and offhand test at the trial, as to his experience, his ability and discrimination as an expert, so that in case of his failure to meet the test he can be held up to ridicule before the jury, and thus the laughter at his expense will cause the jury to forget anything of weight that he has said against you. ”

“ With such limited qualification it is no matter of surprise that expert testimony is sometime made to appear at very great disadvantage. Incompetent and mercenary witnesses will seek employment, and since there are always two sides to a case, and on each side lawyers who spare no efforts for victory, there is a chance for every kind of witness, as there is for every kind of attorney. ”

“ The testimony of an expert is without doubt the most dangerous kind of evidence when not supported by additional testimony; but, on the other hand, if the known facts fit in well, it is the strongest kind of testimony that can be submitted, and is usually known as "opinioned evidence." ”

“ Justice Van Devanter, when circuit judge, that expert testimony not only is unnecessary but indeed may properly be excluded in the discretion of the trial judge 'if all the primary facts can be accurately and intelligibly described to the jury, and if they, as men of common understanding, are as capable of comprehending the primary facts and of drawing correct conclusions from them as are witnesses possessed of special or peculiar training, experience, or observation in respect of the subject under investigation * * *.' United States Smelting Co. ”

“ In other words, the court will seek the aid of opinion evidence only where the issues involved or facts are of such a complex nature that the man of ordinary understanding is not competent or qualified to form an opinion, but, if the court please, even this exception is limited by the rule of law to which I shall refer later in my argument, that prohibits in any event the introduction of expert testimony upon the very facts that the jury are to pass upon. ”

“ If, on the other hand, his answer is too full or he appears too eager, he may create a prejudice against him which nothing can overthrow, and which the art of counsel upon the other side in cross-examination and in making comments upon his testimony when summing up before the jury, will very effectually use to destroy his weight as an expert. ”

“ Yet by their position judges are, of all classes of men, the farthest removed from popular influences of this nature. Their habits of legal investigation, fit them in an eminent degree to weigh with scrupulous accuracy the characters of witnesses; to detect improbabilities and contradictions. Stories that may deceive even intelligent men unacquainted with the laws of evidence, and the bearings of testimony, stand revealed at first glance to the practised eye of the judge as a tissue of falsehoods. ”

“ Every lawyer knows how lightly the evidence of a non-mi-recordo witness is esteemed. The testimony of false witnesses will not be uniform in its texture, but will be unequal, unnatural, and inconsistent. ”

“ With the jury keenly alive to all the possibilities of error in the testimony of even the most honest of witnesses, it is for the advocate, the psychologist of the law, to test by his cross-examination and demonstrate in his summing up the precise probative value of the evidence, frequently revealing, below an apparently limpid stream of truth, a turbid bed of conjecture, assumption, belief, hearsay, and inaccuracy of expression, with the rank weeds of perjury growing just beneath the surface. ”

“ The touchstone is always credibility; the ultimate measure of testimonial worth is quality and not quantity. Triers of fact in our fact-finding tribunals are, with rare exceptions, free in the exercise of their honest judgment, to prefer the testimony of a single witness to that of many. ”

“ It is the duty of the court to determine the competency of evidence, and to decide all legal questions that arise in the progress of a trial, and consequently, when, assuming that all the testimony adduced by the one or the other party is true, it does or does not support his issue, its duty is to declare this clearly and directly. ”

“ Whenever an objection is raised in opposition to the ordinary presumptions of law, or to the ordinary experience of mankind, the burden of proof is devolved on the objector, by the common and ordinary rules of evidence, and of practice in courts. No lawyer is permitted to argue in disparagement of the intelligence or integrity of a witness, against whom the case itself afforded no particle of testimony. This is sufficient for our purpose, in regard to these witnesses. But more than this is evident, from the minuteness of their narratives, and from their history. ”

“ Whether a witness called to testify to any matter of opinion has such qualifications and knowledge as to make his testimony admissible is a preliminary question for the judge presiding at the trial, and his decision of it is conclusive, unless clearly shown to be erroneous in matter of law. ”

“ They may have never seen nor heard the facts in dispute but because they have had so much experience on similar facts they are allowed to say what they think of facts produced by eye witnesses before the court. As conclusions and opinions may be various, there is at times a great variety in experts, and because the very name of experts implies technicality, there is a feeling in the minds of the jury and the public, that the testimony of experts will befog by a mass of non-understandable terms. ”

“ To be confronted at the trial by and to cross-examine the witnesses against him. Where the testimony of a witness for the prosecution has previously been taken down by question and answers in the presence of the accused or his counsel, the defense having had an opportunity to cross-examine the witness, the deposition of the latter may be read, upon satisfactory proof to the court that he is dead or insane, or cannot with due diligence be found in the islands. ”

“ Then the sleepiest witnesses, even dull ones, wake up: the growth of their interest, and hence of their attention, may be followed step by step; they actually increase in knowledge and their statements gain in reliability. And this simply because they have seen the earnestness of the judge, the importance of the issue, the case, the weighty consequences of making a mistake, the gain in truth through watchfulness and effort, the avoidance of error through attention. In this way the most useful testimony can be obtained from witnesses who, in the beginning, showed only despairing prospects. ”

“ There are many more satisfactory tests of the truth of parol testimony than that of character of the witnesses. Where the facts sworn to are capable of contradiction, they may be proved by others not to be true; and when they are not, the internal evidence is often more convincing than any other. A shrewd witness, who is swearing falsely to something which cannot be disproved by direct testimony, will confine his recollection wholly to that single fact, professing a want of recollection of all the facts and circumstances attending it. ”

“ If your Honor please, and you, Gentlemen of the Jury, you sit in judgment on the lives of your fellow-citizens. You act, you look, like men who are thoroughly imbued with a sense of your responsibility. You have listened attentively to all the details of the testimony. You have listened with admiration to the discussion of the testimony by the distinguished gentlemen who have preceded me. You can not have failed to note the radical difference between the method of treating the evidence by counsel for the defendant and by counsel for the people. One is wrong, altogether wrong ”

“ If a witness is of that character you must throw his entire evidence to the winds, for it is tainted and the fountains of justice should not be tainted with such evidence, and a verdict should not be touched and corrupted with such testimony. You will take the evidence of these defendants as you would take that of any other man, and it is for you to say whether that evidence is true. ”

“ In the present chapter it is proposed to discuss the far more difficult task of exposing, by the arts of cross-examination, the intentional Fraud, the perjured witness. Here it is that the greatest ingenuity of the trial lawyer is called into play; here rules help but little as compared with years of actual experience. What can be conceived more difficult in advocacy than the task of proving a witness, whom you may neither have seen nor heard of before he gives his testimony against you, to be a wilful perjurer, as it were out of his own mouth? ”

“ We have at the same time to bear in mind how much use we actually make of both; even our general rules—e.g., concerning false testimony,—bias, revertibility, special inclinations, etc.—and our doctrines concerning the composition and indirection of testimony, even our rules concerning the value of witnesses and confessions, all these depend upon induction and analogy. We pass by their use in every trial from case to case. A means so frequently and universally used must, however, be altogether reliable, or be handled with the greatest care. ”

“ The person who prepares the witness and examines him can generally have just so much or so little of the truth, or such a version of it, as will suit his case. In closely-contested cases, of fact, testimony thus obtained must always be unsatisfactory and liable to suspicion, especially if the party has had time and opportunity to take it in the regular way. ”

“ As an expert, he could properly aid the jury by such evidence, although it would not be competent to be given by an ordinary witness. It is upon subjects on which the jury are not as well able to judge for themselves as is the witness that an expert as such is expected to testify. ”

“ But then a wise and upright judge, assured of the truth of the evidence in the main, and of the integrity of the individual, will not suffer unessential, apparent inconsistencies to stifle and bury the body of testimony at large, but will either extract from the witness what may account for them, or show them to be immaterial. ”

“ Like findings of fact, state court findings of aggravating circumstances often require a sentencer to "resolve conflicts in the testimony, to weigh the evidence, and to draw reasonable inferences from basic facts to ultimate facts." ”