Chaos - James Gleick [94]
Flow fills his pages. Great rivers like the Mississippi and the Bassin d’Arcachon in France meander in wide curves to the sea. In the sea itself, the Gulf Stream, too, meanders, making loops that swing east and west. It is a giant river of warm water amid cold, as Schwenk said, a river that “builds its own banks out of the cold water itself.” When the flow itself is past or invisible, the evidence of flow remains. Rivers of air leave their mark on the desert sand, showing the waves. The flow of the ebbing tide inscribes a network of veins on a beach. Schwenk did not believe in coincidence. He believed in universal principles, and, more than universality, he believed in a certain spirit in nature that made his prose uncomfortably anthropomorphic. His “archetypal principle” was this: that flow “wants to realize itself, regardless of the surrounding material.”
Within currents, he knew, there are secondary currents. Water moving down a meandering river flows, secondarily, around the river’s axis, toward one bank, down to the riverbed, across toward the other bank, up toward the surface, like a particle spiraling around a doughnut. The trail of any water particle forms a string twisting around other strings. Schwenk had a topologist’s imagination for such patterns. “This picture of strands twisted together in a spiral is only accurate with respect to the actual movement. One does often speak of ‘strands’ of water; they are however not really single strands but whole surfaces, interweaving spatially and flowing past each other.” He saw rhythms competing in waves, waves overtaking one another, dividing surfaces, and boundary layers. He saw eddies and vortices and vortex trains, understanding them as the “rolling” of one surface about another. Here he came as close as a philosopher could to the physicist’s conception of the dynamics of approaching turbulence. His artistic conviction assumed universality. To Schwenk, vortices meant instability, and instability meant that a flow was fighting an inequality within itself, and the inequality was “archetypal.” The rolling of eddies, the unfurling of ferns, the creasing of mountain ranges, the hollowing of animal organs all followed one path, as he saw it. It had nothing to do with any particular medium, or any particular kind of difference. The inequalities could be slow and fast, warm and cold, dense and tenuous, salt and fresh, viscous and fluid, acid and alkaline. At the boundary, life blossoms.
Life, though, was D’Arcy Wentworth Thompson’s territory. This extraordinary naturalist wrote in 1917: “It may be that all the laws of energy, and all the properties of matter, and all the chemistry of all the colloids are as powerless to explain the body as they are impotent to comprehend the soul. For my part, I think not.” D’Arcy Thompson brought to the study of life exactly what Schwenk, fatally, lacked: mathematics. Schwenk argued by analogy. His case—spiritual, flowering, encyclopedic—finally came down to a display of similarities. D’Arcy Thompson’s masterwork, On Growth and Form, shared something of Schwenk’s mood and something of his method. The modern reader wonders how much to credit the meticulous pictures of multipronged falling droplets of liquid, hanging in sinuous tendrils, displayed next to astonishingly similar living jellyfish. Is this just a highbrow case of coincidence? If two forms look alike, must we look for like causes?
D’Arcy Thompson surely stands as the most influential biologist ever left on the fringes of legitimate science. The twentieth century’s revolution in biology, well under way in his lifetime, passed him by utterly. He ignored chemistry, misunderstood