Circumstantial Evidence

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Title:     Circumstantial Evidence
Author: Edwin Lawrence Godkin [More Titles by Godkin]

Some of the letters from clergymen which have been called out by our article on the part recently taken by them in scientific discussion maintain that, although ministers may not be familiar with the facts of science, many of them are fully competent to weigh the arguments founded on these facts put forward by scientific men, and decide whether they have proved their case or not; or, in other words, that we were mistaken in saying that the theological seminaries did not afford severe training in the use of the inductive process, and that it could not be used effectively without knowledge of the matters on which it was used. More than one of these letters points, in support of this view, to the answer of the Rev. Dr. Taylor, of this city, to Professor Huxley's lectures, published some weeks ago in the Tribune, and we believe the Tribune presented the author to the public as "a trained logician."

We have accordingly turned to Dr. Taylor's letter and given it a much more attentive reading than we confess we gave it when it first appeared, for the purpose of seeing whether it was really true that ministers were such dexterous and highly taught dialecticians that they could overthrow a scientific man, even on a subject of which they knew little or nothing--whether, in short, they could really treat the question of evolution algebraically, and, by the mere aid of signs of the meaning of which they were ignorant, put the Huxleys and Darwins to confusion. For Dr. Taylor opens in this way:

"Let it be understood, then, that I have no fault to find with Mr. Huxley as a discoverer of facts or as an exponent of comparative anatomy. In both of these respects he is beyond all praise of mine, and I am ready to sit at his feet; but when he begins to reason from the facts which he sets forth, then, like every other reasoner, he is amenable to the laws of argumentation, and his conclusions are to be tested by the relation which they bear to the premises which he has advanced, and by the proof which he furnishes for the premises themselves."

We pass over, as of no consequence for our present purpose, the various exceptions which he then takes to Huxley's arrangement of his lectures, to the tone of his exceptions, and to his mode of referring to the biblical hypothesis, and come to what he has to say of Huxley's evidence, which he truly calls "circumstantial evidence." The first thing he does is to define circumstantial evidence; but here, at the very outset, we have been surprised to find a logician who conceives himself capable of overhauling the argumentation of the masters of science, going to a lawyer to get "a statement of the principles which regulate the value of circumstantial evidence." This is a matter which lay logicians usually have at their fingers' ends, and we have never known one yet who would not be puzzled by a suggestion that he should do as Dr. Taylor did--go to a "distinguished legal friend" for information as to the conditions of this kind of proof. For, as we have more than once pointed out, lawyers, as such, have no special skill or training in the use of circumstantial evidence as scientific men know it--that is, as evidence which derives all its force from the laws of the human mind. The circumstantial evidence with which lawyers, qua lawyers, are familiar under our system of jurisprudence is an artificial thing created by legislation or custom, with the object of preventing the minds of the jury-- presumably a body of untrained and unlearned men--from being confused or led astray. Moreover, they are only familiar with its use in one very narrow field--human conduct under one set of social conditions. For example, a lawyer might be a very good judge of circumstantial evidence in America, and a very poor one in India or China; might have a keen eye for the probable or improbable in a New England village, and none at all in a Prussian barrack.

A familiar illustration of the restrictions on his experience of it is to be found in the rule which compels the calling of "experts" when there is a question as to any point of science or art. "The words science or art," says Mr. Fitzjames Stephen, "include all subjects on which a course of special study or experience is necessary to the formation of an opinion," and the opinion of such an expert is a "relevant fact." So that Dr. Taylor's "distinguished legal friend," if a good lawyer, would not, in spite of his proficiency in circumstantial evidence, undertake to dispute with Professor Huxley about the relation of the anchitherium, hipparion, and horse; and if Dr. Taylor offered himself for examination on such a point he would be laughed out of court. In none of our courts is the presentation allowed of all the circumstances which strengthen or weaken a probability.

A lawyer, therefore, though he might not be as ill fitted for a scientific discussion as a minister, is, as such, hardly more of an authority on the force and limits of that portion of scientific proof which is drawn from simple observation. Dr. Taylor's consulting one as a final authority as to the very nature of the argument on which he was himself about to sit in judgment is at the outset a suspicious incident. The definition of circumstantial evidence which he got from his legal friend was this:

"The process of proof by circumstantial evidence consists in reasoning from such facts as are known or proved, and thence establishing such as are conjectured to exist. The process is fatally vicious, first, if any material circumstance from which we seek to deduce the conclusion depends itself on conjecture; and, second, if the known facts are not such as to exclude to a reasonable degree of certainty every other hypothesis."

"Now, tried by these two tests," says Dr. Taylor, "the professor's argument was a failure." Taking this definition as it stands, however, we think it will not be difficult to show that Dr. Taylor is not competent to apply the tests, or to say whether the professor's argument is a failure or not.

It is hardly necessary to say that all the evidence in our possession or attainable, with regard to the history of the earth and of animal and vegetable life on its surface, is circumstantial evidence. The sciences of geology, palaeontology, and, to a certain extent, biology are sciences of observation, and but few of their conclusions can be reached or tested by experimentation. They are the result of a collection of facts, observed in various places, at various times, and by various persons, and variously related to other facts; and the collection of these facts, and the arrangement of them, and the formation of a judgment as to their value both positive and relative, form the greater portion of the work of a scientific man in these fields. Professor Huxley's argument, which Dr. Taylor disposes of so summarily, consists of a series of inferences from facts so collected and arranged. They are the things "known or proved," on which, as his legal friend truly says, the reasoning in the process of proof by circumstantial evidence must rest.

Now, Dr. Taylor, by his own confession, is no authority in either geology, biology, or palaeontology. He has neither collected, observed, nor experimented in these fields. He does not know how many facts have been discovered in them, or what bearing they have on other facts in other fields. Therefore, he is entirely unable to say whether Huxley is arguing from things "known or proved" or not. Moreover, he does not, for similar reasons, know whether Huxley's process has been "fatally vitiated" by the dependence of any "material circumstance" on conjecture, or by the insufficiency of the "known facts" to exclude every other hypothesis; for, first, he does not know what is in geological, biological, or palaeontological induction a "material circumstance"--nor does any man know except by prolonged study and observation--and, second, he does not know whether "the known or proved facts" are sufficient to exclude every other hypothesis, because he neither knows what facts are known nor what is the probative force of such as are known. We can, however, make Dr. Taylor's position still clearer by a homely illustration. A wild Indian will, owing to prolonged observation and great acuteness of the senses, tell by a simple inspection of grass or leaf-covered ground, on which a scholar will perceive nothing unusual whatever, that a man has recently passed over it. He will tell whether he was walking or running, whether he carried a burden, whether he was young or old, and how long ago and what hour of the day he went by. He reaches all his conclusions by circumstantial evidence of precisely the same character as that used by the geologist, though he knows nothing about the formal logic or the process of induction. Now, what Dr. Taylor would have us believe is that he can come out of his study and pass judgment on the Indian's reasoning without being able to see one of the "known facts" on which the reasoning rests, or appreciate in any degree which of them is material to the conclusion and which is not, or even to conjecture whether, taken together, they exclude the hypothesis that it was not a man but a cow or a dog which passed over the ground, and not to-day but yesterday that the marks were made.

Dr. Taylor further on makes a display of this inability to appreciate the logical value of scientific facts by asking: "Where is the evidence, scientific or other, that there was evolution? We see these fossils (those of the horse). Huxley says they are as they are because the higher evolved itself out of the lower; we say they are as they are because God created them in series." To recur to the former illustration, it is as if the Indian should show Dr. Taylor the marks on which he relied in his induction, and the doctor should calmly reply: "I see the marks; you say they were made by a man's foot in walking; I, who have never given any attention to the subject, and have never been in the woods before, say they were made by the rain." The fact is that if there were any weight whatever in this kind of talk--if no equality of knowledge were necessary between two disputants--it would enable an ignorant field-hand to sweep away in one sentence the whole science of geology and palaeontology, and even astronomy, and to dispose of every conclusion on any subject drawn from a skilled and experienced balancing of probabilities, or nice mathematical calculation, by simply saying that he was not satisfied with the proofs.

Dr. Taylor's reasons for believing that the appearance of fossil horses with a diminishing number of toes is caused by the creation at separate periods of a four-, a three-, a two-, and a one-toed horse are, he says, "personal, philosophical, historical," and he opposes them with the utmost apparent sincerity to Huxley's assertion that "there can be no scientific evidence" of such creation. The "personal reason" for believing in successive creations of sets of horses with a varying number of toes can, of course, only be the reason so often urged in ball-room disputation--that "I feel it must be so;" the "philosophic reason" can only be the one with which those who have frequented the society of metaphysicians are very familiar, namely, a deduction from some eminent speculator's opinion about the nature of the Supreme Being, the conclusion being apparently that if the Creator wished to diminish the number of a horse's toes, it would not do for him to let one drop into disuse and so gradually disappear, but he would have to make a new horse, on a new design. What Dr. Taylor means by the "historical reason" we can only conjecture from his saying that it is of the same order as his historical reason for believing "that the Bible is the Word of God." The historical reason for this, we presume, is that there are various literary and traditional proofs that the Old Testament was held to be the Word of God by the Jewish nation at a very early period, and was by them transmitted as such to the modern Christian world, and that many of the prophecies contained in it have received partial or a complete fulfilment. But how by a process of this kind, partly literary and partly conjectural, and attended by great difficulties at every step, he would reach a fact of prehistoric times of so much gravity as creation in series, we think it would puzzle Dr. Taylor to explain. Indeed, the mere production in a controversy of this nature of these vague fancies, half pious, half poetical, conjured up in most cases as a help to mental peace, by a leading minister in the character of a logician, is a very remarkable proof of the extent of those defects in clerical education to which we recently called attention.

[The end]
Edwin Lawrence Godkin's essay: Circumstantial Evidence

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