Laws or Comets?

November 4, 2016

When one looks at the long sweep of Big History – a panoramic view of the history of everything from the unfolding of the Universe to the evolution of life to the small human story, with its dazzling technology and bloody wars – a question emerges: do we see regularities in the unfolding of the past, or is history all disorganised confusion – just ‘one damn thing after another’? Are there laws that control the unfolding of history?

Beginning with Isaac Newton in the 17th century, scientists have discovered that there are unbreakable mathematical laws governing the motions of objects and all transformations of energy. This discovery suggested that beneath the seemingly capricious events of daily life there might be an underlying order, and that it might even be possible to discover fundamental laws of history itself. But the search for these hoped-for laws of history has not been very successful.

Planets orbiting stars and glaciers creeping down mountainsides are the kinds of things in the history of the regimes (or separate domains) of the Cosmos and Earth that do obey the mathematical laws of physics, and their motions can be calculated. At some point in Big History, however, something different appeared, making it seem very unlikely that well-formulated laws of human history, especially mathematical ones, can be discovered, or that they even exist. What changed was the appearance of life, in which each cell or each multicellular organism is an independent agent, competing with other agents – seeking to acquire energy and nourishment, and passing its traits on to its offspring if it is successful.

The appearance of living agents took our planet beyond the realm of the phases for which physicists can discover natural laws – plasmas, gases, liquids and solids – and brought into being matter organised in far more complex ways. This, I would suggest, was also the beginning of the regimes of Big History – Life and Humanity – for which natural laws simply might not exist. If this is correct, and there are no deterministic laws governing the history of living organisms or human beings, is there any other way to make sense out of history? Can we find, for example, regularities or patterns in the unfolding of history?

In his provocative book Time’s Arrow, Time’s Cycle (1987), Steven Jay Gould argued that there has long been a difference in views of the past between those who saw history as directional and those who considered it to be cyclical. He argued that the conflict between those two views not only influenced how scholars interpreted human history but was also a central intellectual conflict among the early geologists who developed our first serious understanding of Earth.

Time’s arrow versus time’s cycle was a reasonable dichotomy when geologists and historians had only words to describe the past. The ‘decline of Rome’ and the ‘rise and fall of empires’ were provocative descriptions of the past, suggesting arrows and cycles. Now, however, especially in geology, we have a great richness of quantitative data sets – numerical measures of how things have changed in Earth’s past. In studying those plots of history, I find it hard any longer to see the arrow/cycle dichotomy as fundamental.

The problem is one of time scales. If we look at the temperature history of Earth’s surface, we see trends or cycles depending on the time interval we choose. For the past 10,000 years, temperature has been remarkably constant, but taken over the past million years, the temperature plot is cyclical with glacial and interglacial times alternating over 100,000-year cycles. On shorter or longer time scales, there are cooling trends and warming trends.

Completely unexpectedly, contingency can strike, and we can fall off a ladder, or fall in love, and nothing will ever be the same again

As I look at the way history has unfolded across all the regimes of Big History, I think I see a different dichotomy. On the one hand, I see continuities, made up of trends and cycles, combined in various ways at various time scales. On the other hand, there are contingencies – rare events that make significant changes in history that could not have been predicted very far in advance.

Contingencies are everywhere. In our personal lives, we can pass through long periods of continuity, going to work and returning home every day in a cyclical pattern, and meanwhile gradually getting older and perhaps wiser, which are trends. And then, completely unexpectedly, contingency can strike, and we can fall off a ladder, or fall in love, and nothing will ever be the same again. Human history is riddled with contingency, and this is part of what makes it impossible to find laws controlling history. Contingency is particularly dramatic in warfare, with the outcomes of battles turning on such unpredictable circumstances as the way the wind was blowing or the finding of accidentally lost orders.

Although contingency surrounds us and we can often recognise it, defining contingency turns out to be quite difficult. I have not yet found a satisfactory definition or been able to construct one. My current thinking is that for an event to be considered contingent, it needs to be (1) rare, (2) unpredictable, and (3) significant. But each of those qualities involves ambiguities. And when we try to understand what causes contingency, the situation in the two inanimate regimes of Big History – Cosmos and Earth – seems to be completely different from the situation in the Life and Humanity regimes.

Let us first consider contingency in the Cosmos and Earth regimes, taking the impact that finished off the dinosaurs as an example. Then we will look at contingency in the Life and Humanity regimes, with the Spanish Armada as an example. And, finally, let’s think about the astonishing contingency that lies behind the presence here on Earth of each one of us. In each case we will see to what extent the rare-unpredictable-significant criteria are applicable.

For the two inanimate regimes, the ‘rare’ and ‘significant’ aspects of contingency are not difficult to understand. In the power-law distribution of sizes for many natural objects and events, like the diameters of impacting objects and the magnitudes of earthquakes, larger objects and events are rare compared with smaller ones. Larger events are significant over broader areas and touch more people. It’s the ‘unpredictable’ aspect of contingency that is most interesting.

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