65 2. We apply the same relative terms to successive ideas of this class, which we apply to simple ideas, or the clusters called objects, when successive. We call them antecedent and consequent, or names equivalent; as prior, posterior; first, second; or even successive, which is a name including both antecedent and consequent.
In speaking of the relative terms applied to objects as successive, we had occasion to explain the two important terms, Cause and Effect. We found that Cause and Effect, were only other names for antecedent and consequent, in a certain set of cases. We do not use the terms, Cause and Effect, as synonymous with antecedent and consequent, in those cases in which, though the objects may be antecedent and consequent to our perception, we know not whether they are parts of the same series, or parts of two different series. Within the sphere of our observation, innumerable series of events are going on; and we are observing, first a part of one series, and then a part of another, continually. It is thus constantly happening, that those things, which are immediately antecedent and consequent to our observation, are not parts of the same series, but parts of different series; and, of course, in those antecedents and consequents, there is no constancy; they are accidental, as the course of each man’s attention. This may be illustrated by many familiar instances. There may be 66 immediately before me, a man playing on the violin, one series; another man filing a saw, a second series. My attention may pass immediately from the sight of the man playing on the violin, to the sound produced by the filing of the saw. Playing on the violin, and the disagreeable sound of the file on the saw, are thus antecedent and consequent to my attention. But, as we recognise such antecedents and consequents, as parts of different series of events, we do not call them cause and effect.
There are two cases of antecedents and consequents, even when they are parts of the same series. They may be proximate; or they may be remote; that is, parts of the series, more or fewer, may come between them. It is only to the case of the proximate parts of the same series, that the relatives, cause and effect, are properly and strictly applied. When the series, however, is the same, the intermediate links between any two remote parts are constant. Suppose a series, A, B, C, D; as B is the immediate consequent of A, C the immediate consequent of B, and D the immediate consequent of C; when I know A and D as antecedent and consequent, without knowing the intermediate parts B, and C, there is little inaccuracy in naming A and D cause and effect; because B and C are surely intermediate, and the succession of A and D, though not immediate, is constant. We accordingly do name cause and effect parts of a series thus removed from one another, in all those cases in which the intermediate parts are either unknown to us, or habitually overlooked.
The terms Cause and Effect, thus applied to Objects as antecedent and consequent, are applied also to 67 Thoughts as antecedent and consequent. Thus we say, that Evidence is the cause of Belief; Villany is the cause of Indignation, and so on.
Of objects, antecedent and consequent, we have observed, that innumerable series are existing at the same time; a separate series, of vegetation, for example, in every plant, of animalization in every animal, of composition and decomposition in objects without number. In the mind, however, there is but one train, not various trains at the same time; and therefore, according to the sense above applied to the terms Cause and Effect, each thought in a train is the cause of that which follows it, and each succeeding thought is the effect of that which precedes it.
But if thoughts are reciprocally Cause and Effect; that is to say, if, in trains of thought, the same antecedent is regularly followed by the same consequent, how happens it that all trains of thought are not the same? For if the ideas A, B, C, D, &c., constantly follow one another, every mind into which A may enter, goes on with B, C, D, &c., and hence all such minds should consist of the same trains, that is, should be the same.
Supposing the succession of two thoughts to have that constancy to which we apply the terms cause and effect, trains would still have that variety which we experience. Our trains consist of two distinguishable ingredients; sensations and ideas. Sensations depend upon the innumerable series of objects. They are, therefore, liable to all that variety which attends the perception of those objects. A perpetual variety in sensations produces a perpetual variety in the thoughts which are consequent upon them. The 68 variety of sensation, is even much greater than is commonly supposed. The most active of all our sensations is the sight. But in most objects of sight there are numerous parts. Some of these are more seen, some are less seen; some not seen at all. Of these, the parts that are more seen by one man, are less seen by another; whence it is probable, that from an object of any complexity no two men ever receive precisely the same sensations. There is a striking exemplification of this, in the fact, so constantly observed, of the different manner in which different men are affected by the comparison of two countenances. To one man there appears a strong likeness, where another man cannot discover any. Of the minute particulars, on which the likeness depends, none, or an insufficient number, is embraced by the vision of the one, while the contrary is the case with that of the other.
The variety in the sensations, which mix in the trains of men, is one grand cause of the variety in the ideas, which make up or complete those trains. The variety in the order of those sensations is another cause. We have seen that ideas follow one another, in the order in which the sensations have followed. Thus, a man may be a kind father to his child. The sight of him to the child is habitually accompanied with agreeable sensations. The same man may be a severe master to his slaves. The sight of him to the slaves is habitually accompanied with painful sensations. A corresponding difference exists in the case of the ideas. When his image presents itself to the mind of the child, it is followed by a train of pleasurable ideas, corresponding to the 69 pleasurable sensations which the child has habitually enjoyed in his presence. When his image rises to the mind of the slave, it is followed, from the contrary cause, by ideas of the contrary description.[18]
[18] The author may seem to be anticipating a difficulty which few will feel, when he asks how it happens that all trains of thought are not the same. But what he is enquiring into is not why this happens, but how its happening is consistent with the doctrine he has just laid down. He is guarding against a possible objection to his proposition, that “the succession of two thoughts” has “that constancy to which we apply the terms Cause and Effect.” If (he says) it is by direct causation that an idea raises up another idea with which it is associated; and if it be the nature and the very meaning of a cause, to be invariably followed by its effect; how is it, he asks, that any two minds, which have once had the same idea, do not coincide in their whole subsequent history? And how is it that the same mind, when it gets back to an idea it has had before, does not go on revolving in an eternal round?
Of this difficulty he gives a solution, good as far as it goes—that it is because the train of ideas is interrupted by sensations, which are not the same in different minds, nor in the same mind at every repetition, and which even when they are the same, are connected in different minds with different associations. This is true, but is not the whole truth, and a still more complete explanation of the difficulty might have been given. The author has overlooked a part of the laws of association, of which he was perfectly aware, but to which he does not seem to have been always sufficiently alive. The first point overlooked is, that one idea seldom, perhaps never, entirely fills and engrosses the mind. We have almost always a considerable number of ideas in the mind at once; and it must be a very rare occurrence for any two persons, or for the same person twice over, to have exactly the same collection of ideas present, each in the same relative intensity. For this reason, were there no other, the ideas which the mental state excites by association are almost always more or less different.