Like most of his generation, Adams had taken the word of science that the new unit was as good as found. It would not be an intelligence — probably not even a consciousness — but it would serve. He passed sixty years waiting for it, and at the end of that time, on reviewing the ground, he was led to think that the final synthesis of science and its ultimate triumph was the kinetic theory of gases; which seemed to cover all motion in space, and to furnish the measure of time. So far as he understood it, the theory asserted that any portion of space is occupied by molecules of gas, flying in right lines at velocities varying up to a mile in a second, and colliding with each other at intervals varying up to 17,750,000 times in a second. To this analysis — if one understood it right — all matter whatever was reducible, and the only difference of opinion in science regarded the doubt whether a still deeper analysis would reduce the atom of gas to pure motion.
Thus, unless one mistook the meaning of motion, which might well be, the scientific synthesis commonly called Unity was the scientific analysis commonly called Multiplicity. The two things were the same, all forms being shifting phases of motion. Granting this ocean of colliding atoms, the last hope of humanity, what happened if one dropped the sounder into the abyss — let it go — frankly gave up Unity altogether? What was Unity? Why was one to be forced to affirm it?
Here everybody flatly refused help. Science seemed content with its old phrase of "larger synthesis," which was well enough for science, but meant chaos for man. One would have been glad to stop and ask no more, but the anarchist bomb bade one go on, and the bomb is a powerful persuader. One could not stop, even to enjoy the charms of a perfect gas colliding seventeen million times in a second, much like an automobile in Paris. Science itself had been crowded so close to the edge of the abyss that its attempts to escape were as metaphysical as the leap, while an ignorant old man felt no motive for trying to escape, seeing that the only escape possible lay in the form of vis a tergo commonly called Death. He got out his Descartes again; dipped into his Hume and Berkeley; wrestled anew with his Kant; pondered solemnly over his Hegel and Schopenhauer and Hartmann; strayed gaily away with his Greeks — all merely to ask what Unity meant, and what happened when one denied it.
Apparently one never denied it. Every philosopher, whether sane or insane, naturally affirmed it. The utmost flight of anarchy seemed to have stopped with the assertion of two principles, and even these fitted into each other, like good and evil, light and darkness. Pessimism itself, black as it might be painted, had been content to turn the universe of contradictions into the human thought as one Will, and treat it as representation. Metaphysics insisted on treating the universe as one thought or treating thought as one universe; and philosophers agreed, like a kinetic gas, that the universe could be known only as motion of mind, and therefore as unity. One could know it only as one's self; it was psychology.
Of all forms of pessimism, the metaphysical form was, for a historian, the least enticing. Of all studies, the one he would rather have avoided was that of his own mind. He knew no tragedy so heartrending as introspection, and the more, because — as Mephistopheles said of Marguerite — he was not the first. Nearly all the highest intelligence known to history had drowned itself in the reflection of its own thought, and the bovine survivors had rudely told the truth about it, without affecting the intelligent. One's own time had not been exempt. Even since 1870 friends by scores had fallen victims to it. Within five-and-twenty years, a new library had grown out of it. Harvard College was a focus of the study; France supported hospitals for it; England published magazines of it. Nothing was easier than to take one's mind in one's hand, and ask one's psychological friends what they made of it, and the more because it mattered so little to either party, since their minds, whatever they were, had pretty nearly ceased to reflect, and let them do what they liked with the small remnant, they could scarcely do anything very new with it. All one asked was to learn what they hoped to do.
Unfortunately the pursuit of ignorance in silence had, by this time, led the weary pilgrim into such mountains of ignorance that he could no longer see any path whatever, and could not even understand a signpost. He failed to fathom the depths of the new psychology, which proved to him that, on that side as on the mathematical side, his power of thought was atrophied, if, indeed, it ever existed. Since he could not fathom the science, he could only ask the simplest of questions: Did the new psychology hold that the IvXn — soul or mind — was or was not a unit? He gathered from the books that the psychologists had, in a few cases, distinguished several personalities in the same mind, each conscious and constant, individual and exclusive. The fact seemed scarcely surprising, since it had been a habit of mind from earliest recorded time, and equally familiar to the last acquaintance who had taken a drug or caught a fever, or eaten a Welsh rarebit before bed; for surely no one could follow the action of a vivid dream, and still need to be told that the actors evoked by his mind were not himself, but quite unknown to all he had ever recognized as self. The new psychology went further, and seemed convinced that it had actually split personality not only into dualism, but also into complex groups, like telephonic centres and systems, that might be isolated and called up at will, and whose physical action might be occult in the sense of strangeness to any known form of force. Dualism seemed to have become as common as binary stars. Alternating personalities turned up constantly, even among one's friends. The facts seemed certain, or at least as certain as other facts; all they needed was explanation.
This was not the business of the searcher of ignorance, who felt himself in no way responsible for causes. To his mind, the compound IvXn took at once the form of a bicycle-rider, mechanically balancing himself by inhibiting all his inferior personalities, and sure to fall into the sub-conscious chaos below, if one of his inferior personalities got on top. The only absolute truth was the sub-conscious chaos below. which every one could feel when he sought it.
Whether the psychologists admitted it or not, mattered little to the student who, by the law of his profession, was engaged in studying his own mind. On him, the effect was surprising. He woke up with a shudder as though he had himself fallen off his bicycle. If his mind were really this sort of magnet, mechanically dispersing its lines of force when it went to sleep, and mechanically orienting them when it woke up — which was normal, the dispersion or orientation? The mind, like the body, kept its unity unless it happened to lose balance, but the professor of physics, who slipped on a pavement and hurt himself, knew no more than an idiot what knocked him down, though he did know — what the idiot could hardly do — that his normal condition was idiocy, or want of balance, and that his sanity was unstable artifice. His normal thought was dispersion, sleep, dream, inconsequence; the simultaneous action of different thought-centres without central control. His artificial balance was acquired habit. He was an acrobat, with a dwarf on his back, crossing a chasm on a slack-rope, and commonly breaking his neck.
By that path of newest science, one saw no unity ahead — nothing but a dissolving mind — and the historian felt himself driven back on thought as one continuous Force, without Race, Sex, School, Country, or Church. This has been always the fate of rigorous thinkers, and has always succeeded in making them famous, as it did Gibbon, Buckle, and Auguste Comte. Their method made what progress the science of history knew, which was little enough, but they did at last fix the law that, if history ever meant to correct the errors she made in detail, she must agree on a scale for the whole. Every local historian might defy this law till history ended, but its necessity would be the same for man as for space or time or force, and without it the historian would always remain a child in science.
Any schoolboy could see that man as a force must be measured by motion, from a fixed point. Psychology helped here by suggesting a unit — the point of history when man held the highest idea of himself as a unit in a unified universe. Eight or ten years of study had led Adams to think he might use the century 1150-1250, expressed in Amiens Cathedral and the Works of Thomas Aquinas, as the unit from which he might measure motion down to his own time, without assuming anything as true or untrue, except relation. The movement might be studied at once in philosophy and mechanics. Setting himself to the task, he began a volume which he mentally knew as "Mont-Saint-Michel and Chartres: a Study of Thirteenth-Century Unity." From that point he proposed to fix a position for himself, which he could label: "The Education of Henry Adams: a Study of Twentieth-Century Multiplicity." With the help of these two points of relation, he hoped to project his lines forward and backward indefinitely, subject to correction from any one who should know better. Thereupon, he sailed for home.