THE ASSOCIATION OF IDEAS

In my last talk, in treating of Habit, I chiefly had in mind our motor habits,- habits of external conduct. But our thinking and feeling processes are also largely subject to the law of habit, and one result of this is a phenomenon which you all know under the name of the association of ideas.' To that phenomenon I ask you now to turn.

You remember that consciousness is an everflowing stream of objects, feelings, and impulsive tendencies. We saw already that its phases or pulses are like so many fields or waves, each field or wave having usually its central point of liveliest attention, in the shape of the most prominent object in our thought, while all around this lies a margin of other objects more dimly realized, together with the margin of emotional and active tendencies which the whole entails. Describing the mind thus in fluid terms, we cling as close as possible to nature. At first sight, it might seem as if, in the fluidity of these successive waves,

everything is indeterminate. But inspection

shows that each wave has a constitution which can be to some degree explained by the constitution of the waves just passed away. And this relation of the wave to its predecessors is expressed by the two fundamental laws of association,' socalled, of which the first is named the Law of Contiguity, the second that of Similarity.

The Law of Contiguity tells us that objects thought of in the coming wave are such as in some previous experience were next to the objects represented in the wave that is passing away. The vanishing objects were once formerly their neighbors in the mind. When you recite the alphabet or your prayers, or when the sight of an object reminds you of its name, or the name reminds you of the object, it is through the law of contiguity that the terms are suggested to the mind.

The Law of Similarity says that, when contiguity fails to describe what happens, the coming objects will prove to resemble the going objects, even though the two were never experienced together before. In our flights of fancy,' this is frequently the case.

If, arresting ourselves in the flow of reverie, we ask the question, "How came we to be think

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THE TWO LAWS OF ASSOCIATION

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ing of just this object now?" we can almost always trace its presence to some previous object which has introduced it to the mind, according to one or the other of these laws. The entire routine of our memorized acquisitions, for example, is a consequence of nothing but the Law of Contiguity. The words of a poem, the formulas of trigonometry, the facts of history, the properties of material things, are all known to us as definite systems or groups of objects which cohere in an order fixed by innumerable iterations, and of which any one part reminds us of the others. In dry and prosaic minds, almost all the mental sequences flow along these lines of habitual routine repetition and suggestion.

In witty, imaginative minds, on the other hand, the routine is broken through with ease at any moment; and one field of mental objects will suggest another with which perhaps in the whole history of human thinking it had never once before been coupled. The link here is usually some analogy between the objects successively thought of,— an analogy often so subtle that, although we feel it, we can with difficulty analyze its ground; as where, for example, we find something masculine in the color red and something feminine in the

color pale blue, or where, of three human beings' characters, one will remind us of a cat, another of a dog, the third perhaps of a cow.

Psychologists have of course gone very deeply into the question of what the causes of association may be; and some of them have tried to show that contiguity and similarity are not two radically diverse laws, but that either presupposes the presence of the other. I myself am disposed to think that the phenomena of association depend on our cerebral constitution, and are not immediate consequences of our being rational beings. In other words, when we shall have become disembodied spirits, it may be that our trains of consciousness will follow different laws. These questions are discussed in the books on psychology, and I hope that some of you will be interested in following them there. But I will, on the present occasion, ignore them entirely; for, as teachers, it is the fact of association that practically concerns you, let its grounds be spiritual or cerebral, or what they may, and let its laws be reducible, or non-reducible, to one. Your pupils, whatever else they are, are at any rate little pieces of associating machinery.

Their education consists in the organizing

within them of determinate tendencies to associate one thing with another, impressions with consequences, these with reactions, those with results, and so on indefinitely. The more copious the associative systems, the completer the individual's adaptations to the world.

The teacher can formulate his function to himself therefore in terms of association' as well as in terms of native and acquired reaction.' It is mainly that of building up useful systems of association in the pupil's mind. This description sounds wider than the one I began by giving. But, when one thinks that our trains of associa tion, whatever they may be, normally issue in acquired reactions or behavior, one sees that in a general way the same mass of facts is covered by both formulas.

It is astonishing how many mental operations we can explain when we have once grasped the principles of association. The great problem which association undertakes to solve is, Why does just this particular field of consciousness, constituted in this particular way, now appear before my mind? It may be a field of objects imagined; it may be of objects remembered or of objects perceived; it include an action resolved on. In either case,

may