For a number of years Langley had published in his Smithsonian Reports the revolutionary papers that foretold the overthrow of nineteenth-century dogma, and among the first was the famous address of Sir William Crookes on psychical research, followed by a series of papers on Roentgen and Curie, which had steadily driven the scientific lawgivers of Unity into the open; but Karl Pearson was the first to pen them up for slaughter in the schools. The phrase is not stronger than that with which the "Grammar of Science" challenged the fight: "Anything more hopelessly illogical than the statements with regard to Force and Matter current in elementary textbooks of science, it is difficult to imagine," opened Mr. Pearson, and the responsible author of the "elementary textbook," as he went on to explain, was Lord Kelvin himself. Pearson shut out of science everything which the nineteenth century had brought into it. He told his scholars that they must put up with a fraction of the universe, and a very small fraction at that--the circle reached by the senses, where sequence could be taken for granted--much as the deep-sea fish takes for granted the circle of light which he generates. "Order and reason, beauty and benevolence, are characteristics and conceptions which we find solely associated with the mind of man." The assertion, as a broad truth, left one's mind in some doubt of its bearing, for order and beauty seemed to be associated also in the mind of a crystal, if one's senses were to be admitted as judge; but the historian had no interest in the universal truth of Pearson's or Kelvin's or Newton's laws; he sought only their relative drift or direction, and Pearson went on to say that these conceptions must stop: "Into the chaos beyond sense-impressions we cannot scientifically project them." We cannot even infer them: "In the chaos behind sensations, in the 'beyond' of sense-impressions, we cannot infer necessity, order or routine, for these are concepts formed by the mind of man on this side of sense-impressions"; but we must infer chaos: "Briefly chaos is all that science can logically assert of the supersensuous." The kinetic theory of gas is an assertion of ultimate chaos. In plain words, Chaos was the law of nature; Order was the dream of man.
No one means all he says, and yet very few say all they mean, for words are slippery and thought is viscous; but since Bacon and Newton, English thought had gone on impatiently protesting that no one must try to know the unknowable at the same time that every one went on thinking about it. The result was as chaotic as kinetic gas; but with the thought a historian had nothing to do. He sought only its direction. For himself he knew, that, in spite of all the Englishmen that ever lived, he would be forced to enter supersensual chaos if he meant to find out what became of British science--or indeed of any other science. From Pythagoras to Herbert Spencer, every one had done it, although commonly science had explored an ocean which it preferred to regard as Unity or a Universe, and called Order. Even Hegel, who taught that every notion included its own negation, used the negation only to reach a "larger synthesis," till he reached the universal which thinks itself, contradiction and all. The Church alone had constantly protested that anarchy was not order, that Satan was not God, that pantheism was worse than atheism, and that Unity could not be proved as a contradiction. Karl Pearson seemed to agree with the Church, but every one else, including Newton, Darwin and Clerk Maxwell, had sailed gaily into the supersensual, calling it:--
"One God, one Law, one Element,
And one far-off, divine event,
To which the whole creation moves."
Suddenly, in 1900, science raised its head and denied.
Yet, perhaps, after all, the change had not been so sudden as it seemed. Real and actual, it certainly was, and every newspaper betrayed it, but sequence could scarcely be denied by one who had watched its steady approach, thinking the change far more interesting to history than the thought. When he reflected about it, he recalled that the flow of tide had shown itself at least twenty years before; that it had become marked as early as 1893; and that the man of science must have been sleepy indeed who did not jump from his chair like a scared dog when, in 1898, Mme. Curie threw on his desk the metaphysical bomb she called radium. There remained no hole to hide in. Even metaphysics swept back over science with the green water of the deep-sea ocean and no one could longer hope to bar out the unknowable, for the unknowable was known.
The fact was admitted that the uniformitarians of one's youth had wound about their universe a tangle of contradictions meant only for temporary support to be merged in "larger synthesis," and had waited for the larger synthesis in silence and in vain. They had refused to hear Stallo. They had betrayed little interest in Crookes. At last their universe had been wrecked by rays, and Karl Pearson undertook to cut the wreck loose with an axe, leaving science adrift on a sensual raft in the midst of a supersensual chaos. The confusion seemed, to a mere passenger, worse than that of 1600 when the astronomers upset the world; it resembled rather the convulsion of 310 when the Civitas Dei cut itself loose from the Civitas Romae, and the Cross took the place of the legions; but the historian accepted it all alike; he knew that his opinion was worthless; only, in this case, he found himself on the raft, personally and economically concerned in its drift.
English thought had always been chaos and multiplicity itself, in which the new step of Karl Pearson marked only a consistent progress; but German thought had affected system, unity, and abstract truth, to a point that fretted the most patient foreigner, and to Germany the voyager in strange seas of thought alone might resort with confident hope of renewing his youth. Turning his back on Karl Pearson and England, he plunged into Germany, and had scarcely crossed the Rhine when he fell into libraries of new works bearing the names of Ostwald, Ernst Mach, Ernst Haeckel, and others less familiar, among whom Haeckel was easiest to approach, not only because of being the oldest and clearest and steadiest spokesman of nineteenth-century mechanical convictions, but also because in 1902 he had published a vehement renewal of his faith. The volume contained only one paragraph that concerned a historian; it was that in which Haeckel sank his voice almost to a religious whisper in avowing with evident effort, that the "proper essence of substance appeared to him more and more marvellous and enigmatic as he penetrated further into the knowledge of its attributes--matter and energy--and as he learned to know their innumerable phenomena and their evolution." Since Haeckel seemed to have begun the voyage into multiplicity that Pearson had forbidden to Englishmen, he should have been a safe pilot to the point, at least, of a "proper essence of substance" in its attributes of matter and energy: but Ernst Mach seemed to go yet one step further, for he rejected matter altogether, and admitted but two processes in nature--change of place and interconversion of forms. Matter was Motion--Motion was Matter--the thing moved.
A student of history had no need to understand these scientific ideas of very great men; he sought only the relation with the ideas of their grandfathers, and their common direction towards the ideas of their grandsons. He had long ago reached, with Hegel, the limits of contradiction; and Ernst Mach scarcely added a shade of variety to the identity of opposites; but both of them seemed to be in agreement with Karl Pearson on the facts of the supersensual universe which could be known only as unknowable.
With a deep sigh of relief, the traveller turned back to France. There he felt safe. No Frenchman except Rabelais and Montaigne had ever taught anarchy other than as path to order. Chaos would be unity in Paris even if child of the guillotine. To make this assurance mathematically sure, the highest scientific authority in France was a great mathematician, M. Poincaré of the Institut, who published in 1902 a small volume called "La Science et l'Hypothèse," which purported to be relatively readable. Trusting to its external appearance, the traveller timidly bought it, and greedily devoured it, without understanding a single consecutive page, but catching here and there a period that startled him to the depths of his ignorance, for they seemed to show that M. Poincaré was troubled by the same historical landmarks which guided or deluded Adams himself: "[In science] we are led," said M. Poincaré, "to act as though a simple law, when other things were equal, must be more probable than a complicated law. Half a century ago one frankly confessed it, and proclaimed that nature loves simplicity. She has since given us too often the lie. To-day this tendency is no longer avowed, and only as much of it is preserved as is indispensable so that science shall not become impossible."
Here at last was a fixed point beyond the chance of confusion with self-suggestion. History and mathematics agreed. Had M. Poincaré shown anarchistic tastes, his evidence would have weighed less heavily; but he seemed to be the only authority in science who felt what a historian felt so strongly--the need of unity in a universe. "Considering everything we have made some approach towards unity. We have not gone as fast as we hoped fifty years ago; we have not always taken the intended road; but definitely we have gained much ground." This was the most clear and convincing evidence of progress yet offered to the navigator of ignorance; but suddenly he fell on another view which seemed to him quite irreconcilable with the first: "Doubtless if our means of investigation should become more and more penetrating, we should discover the simple under the complex; then the complex under the simple; then anew the simple under the complex; and so on without ever being able to foresee the last term."