one or all must be rejected. Of two contradictory statements, one must be false.

Credibility.

There are three ways of destroying the credibility of a witness (1) by assailing his reputation for veracity, and showing through other testimony that he has made different statements at different times; (2) Destroying by proving a different state of facts through different witnesses; (3) by making him contradict himself on cross-examination. The third is the most effective. It obviates all question as to reliability of other witnesses. Lawyers have three purposes in cross-examination: (1) to elicit more truth; (2) to test the witness's truthfulness by endeavoring to confuse him and make him contradict himself; (3) to lay a foundation for impeachment. Whether any of these ends are reached or not depends on the disposition of the witness, and the manner of conducting the examination. Whatever the purpose, a witness is entitled to fair treatment. Judge Walker says 1:

"Above all things, let counsel who aim at truth, avoid the manner of examination called brow-beating. There are instances warranting sharp and severe treatment of a witness, but they are rare and exceptional. Courtesy is far more successful than harshness. It pays to consider a witness a gentle

To be of account all new evidence must be in harmony with what is already known in the case. Hence the value of corroborating testimony and of concurrent circumstances. A distinction is to be made here be

1 Modern Jury Trials, 217.

2 See the way in which Erskine sifts the testimony of the witness, Hay, on the trial of Lord George Gordon, Goodrich's British Eloquence,'

664.

Circum

tween what is actually known, that is, well-established facts, and what is generally accepted theory. Apparently The apparent discrepancies between new dis- Conflicting coveries and what is thought to be already stances. established, often annoys the most careful scientific investigators. It seemed for a time that one of Pasteur's theories would not conform to what was considered already known:

"Our tendency to select for observation the details which support our existing theories, is so common that it hardly needs illustration. But that a wrong selection may be made even when our object is to attack a theory, the follow- Pasteur. ing example will show. When Pasteur was in

vestigating the causes of splenic fever, he adopted very early in the inquiry the theory of Davaine, that the disease was due to the presence of a certain parasite in the blood, and that consequently the same disease, showing the presence of the same parasite, could be communicated to other animals by inoculation. On the other side, two professors to whom the theory did not commend itself brought forward, as a triumphant refutation of it, what seemed at first a plainly contradictory fact. They had inoculated some rabbits with the blood of an animal which had died of splenic fever, and though the rabbits had died very rapidly no trace of the expected parasite had been found in them either before or after their death. Moreover their blood again had been used to inoculate other rabbits, and these too had died in the same rapid manner, but with the same disregard of what the theory further required. Davaine at once disputed the fact. That is to say, he insisted that the two professors must have used blood which was not properly infected with splenic fever, but with some other disease. The professors, however, were equally certain of their facts; they had got their materials from the best available source, namely, from the director of an establishment where numerous animals which had died of splenic fever were constantly brought. But in order to convince the stubborn theorist they tried the experi

ment again, this time obtaining their materials from the most experienced veterinary surgeon in the neighborhood. Exactly the same result followed, and the facts certainly here appeared to be too strong for the theory.

"It was some years later when the real weakness of the facts themselves came to light. Davaine's theory had meanwhile been enlarged and improved by the discovery that if the blood used for inoculation has already begun to putrefy, the animals inoculated will die by a form of blood-poisoning, quicker in its operation than splenic fever, and too quick to allow the true splenic fever parasites time to multiply. This suggested a new inquiry into the professors' experiments, and it was found that the blood used by them, although certainly taken from cases of splenic fever, had not been sufficiently fresh. So that the fact on which they had relied as contradicting the theory turned out to be wrongly—i.e., incompletely described. Through merely overlooking the detail that the animals whose blood they used had been dead some twenty-four hours, their description of it as splenic fever blood' became essentially false."1

Proposition.

The character of the proposition on which evidence is adduced, must modify somewhat its validity. No evidence of any force could be used to show that the universe has always existed in its present Character of state. Testimonial evidence would have little force to sustain what Huxley calls the "Miltonic" theory. Even on what is called the “Evolution” theory there are two classes of evidence between which there seems to be an irreconcilable conflict.

"I have not the slightest means of guessing whether it took a million of years, or ten millions, or a hundred ble Conflicts. millions, or a thousand millions to give rise to that series of changes. A biologist has no means of

Irreconcila

Huxley.

1 Sidgwick, Process of Argument, 94.

arriving at any conclusion as to the amount of time which may be needed for a certain quantity of organic change. He takes his time from the geologist. The geologist, considering the rate at which deposits are formed and the rate at which denudation goes on upon the surface of the earth, arrives at more or less justifiable conclusions as to the time which is required for the deposit of a certain thickness of rocks; and if he tells me that the tertiary formations required 500,000,000 years for their deposit, I suppose he has good ground for what he says, and I take that as a measure of the duration of the evolution of the horse from the Orohippus up to its present condition. And, if he is right, undoubtedly evolution is a very slow process, and requires a great deal of time. But suppose, now, that an astronomer or a physicist - for instance, my friend Sir William Thomson tells me that my geological authority is quite wrong; and that he has weighty evidence to show that life could not possibly have existed upon the surface of the earth 500,000,000 years ago, because the earth would have then been too hot to allow of life, my reply is: That is not my affair; settle that with the geologist, and when you have come to an agreement among yourselves I will adopt your conclusion.' We take our time from the geologists and physicists; and it is monstrous that, having taken our time from the physical philosopher's clock, the physical philosopher should turn round upon us, and say we are too fast or too slow. What we desire to know is, is it a fact that evolution took place? As to the amount of time which evolution may have occupied, we are in the hands of the physicist and the astronomer, whose business it is to deal with those questions."1

The uncontradicted testimony of a single witness in court, unless absurd on its face or lacking all probability from its very nature, may be so valid as to determine a case. But the unsupported asser- Assertion. tion of an advocate or other reasoner, unless

he is an

Bare

accepted authority, will have little weight.

1 Huxley, American Addresses, 92.

When a clergyman says, "No editor will tell the truth unless he is compelled to," the critical hearer demands evidence. His experience does not teach him that one class of men are liars above all others. He says with Huxley: "For my part, I have no prejudice one way or the other. If there is evidence in favor of this view, I am burdened by no theoretical difficulties in the way of accepting it; but there must be evidence. Scientific men get an awkward habit—no, I won't call it that, for it is a valuable habit of believing nothing unless there is evidence for it; and they have a way of looking upon belief which is not based upon evidence, not only as illogical but as immoral.”1

Political
Writing.

How little mere assertion proves, and how it differs from evidence or reasoning upon evidence, is shown in the following notice of a volume on proportional representation:

"The benefits to be expected from the adoption of proportional representation are, if its advocates are to be believed, of the most exalted kind. They assert that it would make the voters independent of party machinery, put an end to gerrymandering and the spoils system, raise the personal character of legislators, and purify the whole atmosphere of politics. Representative government as it now exists, they say, is a failure and only the adoption of proportional representation will avail to save it. When, however, we inquire on what these rosy expectations are founded, we find that, except as to the abolition of gerrymandering, they have no foundation at all. The advocates of the proposed system tell us that it would insure us representatives of high moral and intellectual character; but we look in vain for a connection between their assertions and their conclusion. With the same voters to make the choice, and the same men to choose from, how can a different grouping of the voters secure a wiser choice?" 2