The Science of Simplicity

Why do scientists pursue the simple solution?

When scientists, usually physicists, wax lyrical about the importance of elegance and simplicity to their enterprise, non-scientists are bound to conclude that their sense of “elegance” or “simplicity” is rather peculiar. After all, science, in both conduct and content, is difficult and complicated – and increasingly contested. But maybe this only shows how little the lay person knows about science. It is still by no means obvious that the different sciences share any common standards of elegance and simplicity.

Indeed, the received wisdom amongst philosophers of science these days is that there is no overarching sense of elegance and simplicity to be had. The very idea is likely to be dismissed as the result of an unholy conspiracy between Platonists and positivists who would have us believe that certain perspicuous patterns in nature are self-validating. It would be as if science were a sophisticated version of finding faces in clouds or inferring aliens from crop circles.

According to this received wisdom, elegance and simplicity are ultimately matters of personal aesthetics, the objective basis of which can all too easily be overestimated. After all, drawing the simplest curve to capture a scatter of data points only makes sense if the scatter is representative of the reality you’re trying to capture. Of course, modern statistics is precisely about how to make such judgements, but much room remains for error.

Nevertheless, for better for worse, our Platonist and positivist conspirators are getting a new lease of life with the dawn of big data, a side-effect of our increased powers of surveillance and computation.  The argument here is that we’re forced to look for simple and elegant patterns if we want to take control of the ongoing information overload. Aesthetics is no longer an optional extra but an epistemic survival strategy. Nowadays algorithms are developed to extract needles from the data haystacks, while evolutionary psychologists explain how the search for elegance and simplicity is hard-wired into our cognitive apparatus.

But all of this has little to do with the original reason why scientists thought that elegance and simplicity might provide the royal road to reality. That is the belief that reality has been created in such a way that we can understand it. A line of thinkers in the modern era – more or less influenced by Plato – have promoted this idea in various forms, including Leibniz, Kant and the man who coined the word ‘scientist’ in the 19th century, William Whewell. The idea usually goes by the name of ‘intelligibility’.

For reality to be ‘intelligible’, more is required than simply that we can make sense of it well enough to survive and even flourish. After all, animals adapt perfectly well to their native habitats. But at the same time, they normally stay within those habitats, do not do well outside of them and, in any case, do not exhibit any fruitful sense of curiosity about what lies beyond their normal spheres of activity. 

By “fruitful sense of curiosity”, I mean a form of inquiry that aspires to be more than mere gossip about strange lands. It is the idea that what we learn about times and places distant from us is integral to making sense of who we are, where we came from and where we might be going. The intuitive appeal of this elegant and simple idea explains why Newton’s unified account of physical motion, which covers both the Earth and the heavens under a single set of laws, has been treated as the gold standard of scientific achievement for more than three centuries. Today we call it the first “Theory of Everything”.

For their part, animals don’t need to know about everything, and in most cases don’t want to – let alone want to put everything they know into a neat cognitive package, which is the ultimate appeal of elegance and simplicity. We could have been counted amongst those animals for most of human history. Two millennia of Chinese civilisation and the West under the spell of Aristotle show that sophisticated, complex societies can flourish perfectly well without the quest for a Theory of Everything.

In fact, those societies were cautious about seeing the world through a mathematical lens, the context in which elegance and simplicity seem so cognitively luminous. To a scientist, mathematics is a set of techniques for abstracting from empirical reality, especially lived experience. But what enabled a mathematically adept scientist like Newton to see similar patterns across different domains of reality arguably also led him to underestimate, if not altogether overlook, their most distinctive features.

As the poet Goethe famously stressed, Newton left us with a cold, desiccated world-view, alienated from the richness of human sensibility. Yet this is also the world-view that has introduced human beings to new modes of experience associated with the very small, the very large, the very fast and the very slow. Indeed, a strong philosophical intuition behind the idea of intelligibility is that a unified conception of reality allows us to sample the fullest range of experience possible. Science fiction has probably done the most in recent times to strengthen that intuition.

But why would Newton or any other scientist believe that reality is intelligible – especially before this idea began to bear fruit in modern science and technology? The source is ultimately theological, namely, that our own minds match that of reality’s creator, which implies that in some ways our sense of elegance and simplicity is God’s as well. This idea, heretical even in the Christian world whence it came, survives in a thoroughly secular and largely atheistic form in cosmology as the “anthropic principle”. Put roughly but to the point, if the universe were not as elegant and simple as it seems then we wouldn’t be here to know it.


Image credit: Llacertae

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