“The stream of thought is not a continuous current, but a series of distinct ideas, more or less rapid in their succession, the rapidity being measurable by the number that pass through the mind in a given time. Mental excitement is constantly judged of by this test; and if we choose to count and time the thoughts as they succeed one another, we could give so much more precision to the estimate.”[32]
These transitions should not be confounded with the relations between objects of thought or between objects in the external world. The relations may be part of the thought of that which is perceived or known, or they may be made distinct ideas or thoughts. The important phase under consideration is the passage of the mind from one idea or thought to another. Such transitions are quite as important and quite as much a part of the current of thought as the premises and conclusions on which the mind seems to rest. These two phases of the thought-process may be likened to the perching and the flight of a bird. This figure of speech is used by Professor James, among whose services to the profession of teaching it is not the least that he has called attention to the importance of these transitions in the stream of consciousness. His account is so lucid and satisfactory that one cannot forbear to quote his words at some length. Referring to the stream of thought, he says,—
“Like a bird’s life, it seems to be made up of an alternation of flights and perchings. The rhythm of language expresses this, where every thought is expressed in a sentence and every sentence closed by a period. The resting-places are usually occupied by sensorial imaginations of some sort, whose peculiarity is that they can be held before the mind for an indefinite time and contemplated without changing; the places of flight are filled with thoughts of relations, static or dynamic, that for the most part obtain between the matters contemplated in the periods of comparative rest. _Let us call the halting-places_ the ‘substantive’ parts and the places of flight the ‘transitive’ parts of the stream of thought. It then appears that the main need of our thinking is at all times the attainment of some other substantive part than the one from which we have just been dislodged. And we may say that the main use of the transitive parts is to lead us from one substantive conclusion to another. Now it is very difficult, introspectively, to see the transitive parts for what they really are. If they are but flights to a conclusion, stopping them to look at them before a conclusion is reached is really annihilating them. Whilst if we wait until the conclusion be reached, it so exceeds them in vigor and stability that it quite eclipses and swallows them up in its glare. Let any one try to cut a thought in the middle and get a look at its section, and he will see how difficult the introspective observation of the transitive tract is. The rush of the thought is so headlong that it almost always brings us up at the conclusion before we can arrest it. Or if our purpose is nimble enough and we do arrest it, it ceases forthwith to be itself. As a snow-flake crystal caught in the warm hand is no longer a crystal, but a drop, so, instead of catching the feeling of relation moving to its term, we find we have caught some substantive thing, usually the last word we were pronouncing, statistically taken, and with its function, tendency, and particular meaning in the sentence quite evaporated. The attempt at introspective analysis in these cases is, in fact, like seizing a spinning top to catch its motion, or trying to turn up the gas quickly enough to see the darkness. And the challenge to _produce_ these psychoses, which is sure to be thrown by doubting psychologists at any one who contends for their existence, is as unfair as Zeno’s treatment of the advocates of motion, when, asking them to point out in what place an arrow _is_ when it moves, he argues the falsity of their thesis from their inability to make to so preposterous a question an immediate reply.”[33]