Darwin's Slow Time

In 1831 a young college graduate set off on an around the world voyage. On this adventure, which lasted nearly five years, he met gauchos, learned to hunt exotic birds, and escaped a violent revolution in Buenos Aires. Eventually he arrived in Uruguay, where he collected fossils of giant armadillos, ground sloths, and other extinct mammals. The contrast between the sudden violence of human revolution and the slow, less obviously violent change of the earth’s surface must have been telling. In Charles Darwin’s Journal of these years on the HMS Beagle we can see the raw material of what would become his theory of evolution. Perched at the tip of South America, Darwin considered the long pebbled coastline and reflected, “When we consider that all these pebbles, countless as the grains of sand in the desert, have been derived from the slow falling of masses of rock on the old coast-lines and banks of rivers; and that these fragments have been dashed into smaller pieces, and that each of them has since been slowly rolled, rounded, and far transported, the mind is stupefied in thinking over the long, absolutely necessary lapse of years.”

Rock to stone to pebble to sand to dust, all that matter rolled and rounded and moved. Just how long does that take and how slow must that process be? Yes, the mind is stupefied. How can we comprehend the plenitude of time, the sheer number of years necessary for the unfolding of gradual unseen processes to blossom into recognizable significance? The time of evolution requires this plenitude, and slowness itself becomes a product of these increased spans of time.

We can begin to grasp just how long a timescale Darwin’s theory requires when we consider the only illustration that he offers in the Origin of Species, which shows species differentiation over time. This image has fourteen horizontal lines. The interval between each line, Darwin tells us, represents a thousand generations, but he quickly adds that “it would have been better if each had represented ten thousand generations.” Later Darwin qualifies this figure yet again to a million or hundred million generations. A thousand, ten thousand, a million, a hundred million—numbers whose increase in ordinal power exceeds the limit of our imagination, but which represent merely the start of the vast stretches of time that Darwin’s theory requires.

Darwin himself was aware of this problem. His theory required “a lapse of time...so great as to be utterly inappreciable by the human intellect.” How, after all, can we comprehend the significant difference between ten million and a hundred million years, or, for that matter, ten million and eleven million years? And yet this is also the representational problem that Darwin must confront if he wants to make the case for slow and gradual change within an incomprehensibly long time span. To make the imaginative leap, we need to feel the slowness of time. Darwin, for his part, understands the difference that slow time makes, and to render a vast timescale comprehensible he resorts to a visual aid, a printed chart.
Darwin’s chart bears comparison with the work of the now little-known Scottish political economist and engineer, William Playfair, who also used a visual aid to represent slow and gradual processes accumulating over time. For Playfair, the processes were economic and the chart he invented was the now ubiquitous time-series line graph. Both Darwin and Playfair turn to the visual to express what words and numbers fail to convey. While Playfair sought to map known data to create a timesaving device for economic and political decision makers, Darwin moves beyond the timeframe of the human to imagine change on a nearly cosmic scale. Despite this difference, each chart depends upon a uniformity of scale.

Scale is heterochronic: the same spatial representation can be used for very different experiences of time. Darwin’s willingness to expand the significance of each horizontal line in his chart, from a thousand to ten thousand to a million to a hundred million generations, then, indicates not backsliding or confusion on his part, but rather underscores the imaginative force of his visual aid. What is interesting and innovative about Darwin’s chart is that it reveals gradual change across an adaptable range of timescales. It makes slow time available to representation by accounting for vast swathes of time in a single glance. Playfair bragged that with his chart, men could see in five minutes what otherwise took whole days to observe. Darwin’s chart represents slowness and gradual change, but because of its immediate visual power, slow time itself can be grasped instantaneously. And this, perhaps, is the paradox of slow time: if you want to seize it, you’ve got to see it quickly.