suggested two tests. First, he asked whether the commercial dispute did, in order of time, precede the dispute on taxation? As a matter of fact, it followed the dispute on taxation, and consequently could not have been the original cause of the quarrel. Next, he suggested removing the alleged cause and ascertaining whether the effect disappeared at the same time. "To enable us to judge," he said, "whether at this moment a dislike to the trade laws be the real cause of quarrel, it is absolutely necessary to put the taxes out of the question by a repeal. See how the Americans act in this position, and then you will be able to discern correctly what is the true object of the controversy, or whether any controversy at all will remain. Unless you consent to remove this cause of difference, it is impossible, with decency, to assert that the dispute is not upon what it is avowed to be."

If the removal of an assumed cause is followed at once by the disappearance of the observed effect, we have strong presumptive evidence that no other cause produced the effect.

II. ARGUMENT FROM CAUSE TO EFFECT

To attempt to show that a happening is probable, for the reason that there are known antecedent circumstances sufficient to bring about that happening, is to argue from cause to effect. We may argue thus from the past to a less remote past, from the past to the present, from the past to the future, from the present to the future, or from the future to the more remote future. In every case we argue from the known events of one time to the unknown events of a subsequent time.1

1 Sidgwick asserts that the only conceivable aim of any kind of knowledge, whether common or scientific, is this power of dealing with concrete facts through wisdom before the event, · the power of prediction from causes to effects.

This is called a priori reasoning, and is the usual form of what is sometimes called "argument from antecedent probability." The use of the latter term is so much confused that we have thought best to get along without it; though the argument itself is illustrated under various topics.

This kind of argument is common in criminal trials. We ask at once whether the known motive of the accused man was sufficient to prompt him to commit the crime. In arguing from the motive to the crime, we argue from a cause known to be operative to an alleged effect of that cause. As an illustration, let us suppose the question at issue is whether A destroyed his father's will. If the will disinherited A, and named an enemy of A as the legatee of the whole estate, there appears to have been sufficient reason for A to desire the destruction of the will. If we use this motive in an attempt to prove that A is guilty, we argue from a known cause to an effect under dispute. Lawyers in criminal trials frequently attempt to carry the minds of the jury back to the events just preceding the crime, in order to show causes then operative tending to prompt the prisoner at the bar to commit the crime of which he is accused.

In an argument from cause to effect, we must prove the probability that the cause is adequate to produce the alleged effect. If an adequate cause is shown to exist in a given case, the effect which usually follows that cause may reasonably be expected to follow in the case in question. Thus when a doctor finds the symptoms of diphtheria in a patient, he predicts the course of the disease from day to day. When he administers anti-toxin, he foretells the effects. He reasons from cause to effect, from the known events of one time to the unknown events of a later time.

We should always ask whether there are other causes sufficient to prevent the known cause from producing the effect in question. The chemist, in order to determine the effect of a given cause, separates the experiment in the laboratory from every possible cause but one, and his conclusion has scientific accuracy. But the great multitude of questions with which argumentation deals cannot be thus isolated; they are complicated, as we have seen above, by attendant circumstances. Many causes are operating at once. "It sometimes happens

that with perfect sanitary conditions a contagious disease will appear, that has always been regarded, and that correctly, as due to imperfect sanitation; or, an entire disregard of sanitary requirements and of all the laws of health may yet give rise to no disease of special moment. Certain conditions of temperature, atmospheric pressure, velocity, and direction of the wind, may one day bring storm and rain, and as far as observation can detect, similar conditions may again bring fair weather. So, also, the rise and fall in stock and money markets is extremely susceptible to the varying conditions of indefinitely complex forces wholly beyond all powers of determination or of prediction. . . . In such phenomena as these the problem is not simply to find a causal connection. The causal connection may be established beyond all reasonable doubt, and yet the cause obtains in the midst of so complex a setting that the problem is really this, to determine whether a cause, whose exact nature may be known or unknown, will prove operative or inoperative. The cause may be always present, and even its exact nature may be known, and yet the complex circumstances attending it may be of such a character that one alone, or two or more combining, may neutralize the operation of the cause, and on the other hand a slight variation of the combined circumstances may promote and even accelerate the operation of the cause in question." 1

All attempts to prove the probability that an event happened or will happen by setting forth a seemingly sufficient cause are rendered futile by any positive evidence showing that the event did not happen or does not happen. No amount of proof that A desired the destruction of his father's will can prove A guilty in the face of evidence that the will has not been destroyed.

During the fall of 1907 there appeared to be every cause

1 J. G. Hibben, Logic, Deductive and Inductive. (Charles Scribner's Sons, New York, 1905.)

of "good times" throughout the United States. In addition to all the circumstances which had made the previous years highly prosperous, there was the assurance of good crops. Many argued that the effect must be confidence in the money market and stimulation of industry. But this argument concerning what must happen fell down before the facts concerning what did happen, and gave little consolation to the stockholders who lost their securities and to the workmen who lost their positions. Many men maintained that the opening of Stanford University would cause a falling off in numbers of students at the near-by University of California. But this argument was not sustained by facts. Equally liable to error are the presumptions, furnished by the argument from cause to effect, that a given event cannot happen. A lawyer, upon visiting his client in prison and hearing the facts of the case, exclaimed, "Why, they can't put you in prison for that!" "But here I am," replied the client.

"Great is the syllogism!" said Charles Reade, in Peg Woffington. "But there is a class of arguments less vulnerable. If A says to B, 'You can't hit me, as I prove by this syllogism' (here followest the syllogism), and B, pour toute réponse, knocks A down such a whack that he rebounds into a sitting posture; and to him the man, the tree, the lamppost, and the fire-escape, become not clearly distinguishable; this barbarous logic prevails against the logic in Barbara, and the syllogism is in the predicament of Humpty Dumpty."

The following editorial refers to the difficulty in proving that free wool will ruin the industry in the face of facts to the contrary:

One tariff trench out of which the Republicans will find it hard to bomb the Democrats is the one named free wool. A circular letter issued by the First National Bank of Boston dwells upon the unparalleled prosperity of the manufacturers of woolen goods. . . . Now, of course, according to all protectionist logic and predictions, these things could not possibly have happened under free wool. And they will doubtless be described as one of the consequences of an

unforeseen war. That there is reason in this we do not deny; but it is not of a kind that can be used in a calamity-howling hightariff campaign. As the Chicago Tribune admits, the old Republican "trick" about prosperity is "coming home." It remarks shrewdly: "People who have more money than they used to have will be very little interested, we suspect, in arguments telling them that by all the regular rules they ought not to have this money. The answer is that they have it." 1

The argument from cause to effect is evidently inconclusive. It can prepare the way for other arguments by creating presumptions, but it can do no more.

III. ARGUMENT FROM EFFECT TO EFFECT

An argument from one effect to another effect of the same cause is nothing more than an argument from effect to cause fused with an argument from cause to effect. If a boy says that there is skating to-day because the thermometer registers below the freezing-point, he really reasons from the low thermometer to its cause, the low temperature, and from that back to another effect of the same cause, namely, the frozen river. We may note in passing that the whole argument is based on inductive reasoning, which has led to the discovery of the general truth that a temperature below 32 degrees, Fahrenheit, always freezes water. In fact, all arguments from causal relation rest on principles generalized from observed instances.

As another illustration of this telescoped kind of argument from causal relation we may take the reasoning of a man who, when he hears the ticking of a watch, concludes that the hands are moving. He draws an inference from effect to effect of the same cause, namely, the elasticity of the watchspring. In other arguments, even when we have tested our facts and found them actually related as cause and effect, they may act and react upon each other in such a way that

1 The Nation, June 29, 1916.