Chapter XIII · EVIDENCE.
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“In consequence of some very wonderful laws, which regulate the successions of our mental phenomena, the science of mind is, in all its most important respects, a science of analysis.” Brown’s Lect., i., 108.
BEFORE leaving the subject of Belief, it will be proper to shew, in a few words, what is included, under the name Evidence. Evidence, is either the same thing with Belief, or it is the antecedent, of which Belief is the consequent.
Belief we have seen to be of two sorts: Belief of events; Belief of propositions.
Of events, believed on our own experience, the evidence of the present is sense; of the past, memory; and in these cases, the evidence and the belief are not two things, but one and the same thing. The lamp, which at this moment lights me, I say that I see burning, and that I believe it burning. These are two names of one and the same state of consciousness.—“I remember it was burning at the same hour last night,” and “I believe it was burning at the same hour last night,” are also two expressions for the same thing.—In the simple anticipation of the future, from the past, also, the evidence, and the belief, are not two things, but one and the same thing. There is a close and inseparable association of the idea of a like antecedent, with the idea of a like consequent. This has not a single name, like memory; but, like memory, it is both evidence and belief.
The case of testimony is different. The Testimony is one thing, the Belief is another. The name Evidence is given to the testimony. The association of the testimony, with the event testified, is the belief.
Beside the belief of events which are the immediate objects of sense, of memory, and of anticipation (the consequence of sense and memory), and of those which are the immediate objects of testimony; there is a belief of events which are not the immediate objects of any of those operations. The sailor, who is shipwrecked on an unknown coast, sees the prints of a man’s foot on the sand. The print of the foot is here called the evidence; the association of the print, as consequent, with a man, as antecedent, is called the belief. In this case, the sensation of one event, the print of a foot on the sand, induces the belief of another event, the existence of a man. The sailor who has seen the mark, reports it to his companions who have not quitted the wreck. Instantly they have the same belief; but it is a remove farther off, and there is an additional link of evidence. The first event to them, is the affirmation of their companion; the second, the existence of the print; the third, that of the man. There is here evidence of evidence; the testimony, evidence of the print; the print, evidence of the man.
The companions of the sailor, having themselves gone on shore, perceive, indeed, no man, but see a large monkey, which leaves prints on the sand very much resembling those which had first been perceived by their companion. What is now the state of their minds? Doubt. But doubt is a name; what do we call by that name? A phenomenon of some complexity, but of which the elements are not very difficult to trace. There is, here, a double association with the print of the foot. There is the association of a man, and there is the association of a monkey. First, the print raises the idea of a man, but the instant it does so, it raises also the idea of a monkey. The idea of the monkey, displacing that of the man, hinders the first association from the fixity which makes it belief; and the idea of man, displacing that of monkey, hinders the second association from that fixity which constitutes belief.
When evidence is complex; that is, consists of more than one event; the events may be all on the same side, or not all on the same side; that is, they may all tend to prove the same event; or some of them may tend to prove it, some may have an opposite tendency.
Thus, if after discovering the print on the sand, the sailors had seen near it a stick, which had any appearance of having been fashioned into a club, or a spear, this would have been another event, tending, as well as the print on the sand, to the belief of the presence of men. The evidence would have been complex, but all on one side. The process is easy to trace. There is now a double association with the existence of men. The print of the foot excites that idea, the existence of the club excites that idea. This double excitement gives greater permanence to the idea. By repetition, the two exciting causes coalesce, and, by their united strength, call up the associated idea with greater force.
In the case of the appearance of the monkey, in which one of the events tended to one belief, the other to another, we have just seen that the effect is precisely contrary; to lessen the strength of the association with the existence of a man, and to hinder its becoming belief.
These expositions may be applied with ease to the other cases of complex evidence, which can only consist of a greater or less number of events, either all tending to the belief of the same event, or some tending that way, some another; but all operating in the manner which has just been pointed out. Thus we may complicate the present case still further, by the supposition of additional events. After the appearance of the monkey, the sailors may discover, in the neighbourhood, the vestiges of a recent fire, and of the victuals which had been cooked by it. The association of human beings with these appearances is so strong, that, combined with the association between the print and the same idea, it quite obscures the association between the print and the monkey; and the belief that the place has inhabitants becomes complete. But suppose, further; that after a little observation, they discover an English knife, and fork, and a piece of English earthenware near the same place. The idea of an English ship having touched at the place, is immediately excited, and all the evidence of local inhabitants, derived from the marks of fire and cookery, is immediately destroyed. In other words, a new association, that with an English ship, is created, which completely supersedes the idea, formerly associated, that of inhabitants existing on the spot.
The whole of the events, which go in this manner to form a case of belief, or of doubt, or of disbelief, are called Evidence. And the association, which binds them together into a sort of whole, as antecedent, and connects with them the event to which they apply as consequent, and which constitutes the belief, doubt, or disbelief, very often goes by the names of “judgment,” “judging of the evidence,” “weighing the evidence,” and so on.
In these cases of the belief of Events upon complicated evidence, there is an antecedent and a consequent; the antecedent consisting of all the events which are called evidence, the consequent of the event, or events evidenced; and lastly, there is that close association of the antecedent and the consequent, which we have seen already, in so many instances, constitutes belief.
We have now to consider, what we call evidence in the case of the Belief of Propositions.
There are two cases of the Belief of propositions. There is belief in the case of the single proposition; and there is belief of the conclusion of a syllogism, which is the result of a combination of Propositions.
We have seen what the process of belief in Propositions is. The subject and predicate, two names for the same thing, of which the predicate is either of the same extent with the subject, or of a greater extent, suggests, each of them, its meaning; that is, call up, by association, each of them, its peculiar cluster of ideas. Two clusters of ideas are called up in connexion, and that a peculiar connexion, marked by the copula. To have two clusters of ideas, to know that they are two, and to believe that they are two, this is nothing more than three expressions for the same thing. To know that two clusters are two clusters, and to know that they are either the same, or different, is the same with having them. In this case, then, as in that of the belief of events, in sense and memory, the belief and the evidence are the same thing.
Belief of the conclusion of a syllogism, is preceded by two other beliefs. There is belief of the major proposition; belief of the minor proposition; by the process immediately above explained, in which the evidence and the belief are the same thing. These are the antecedent. There is, thirdly, belief of the conclusion, this is the consequent. The process of this belief has been so recently explained, that I do not think we need to repeat it. In this case, it is sometimes said, that the two premises are the evidence; sometimes it is said, that the ratiocination is the evidence; in the former of these applications of the word evidence, the belief of the concluding proposition of the syllogism is not included; in the last, it is. The ratiocination is the belief of all the three propositions; and, in this acceptation of the word, the evidence and the belief are not considered as two things, but one and the same thing. This, however, is only a difference of naming. About the particulars named, there is no room for dispute.110