Nature | Editorial

Second thoughts

Revisiting the past can help to inform ideas of the present.

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The thought experiment has a noble place in research, but some thoughts are deemed more noble than others. Darwin and Einstein could let their minds wander and imagine the consequences of certain actions or natural laws. But scientists and historians who try to estimate what might have happened if, say, Darwin had fallen off the Beagle and drowned, are often accused of playing parlour games.

Most of these counterfactual thought experiments tend to focus on changes to the lives of historical figures — what would have happened had Hitler never been born, for instance. Dismissed as silly and speculative, such exercises are considered of little academic value, because the results of the experiment tend to align with what the experimenter would have wanted to happen. (One of first such published accounts seems to prove the point: Napoléon Apocryphe, published by a supporter in 1841, starts with the emperor surviving the 1812 Russian winter in an unburnt Moscow, conquering Europe, then Asia, Africa and the Americas, while discovering a new planet and inventing a flying car on the way.)

The course of history is surely contingent on the roles of influential individuals, which is why counterfactual tales of thwarted plots succeeding and dictators killed as infants seem so poorly anchored to reality. An individual really can steer events, so a world without that individual is unknowable. But what about the course of science, and the ideas that push it along? Is scientific and technical progress equally contingent on circumstance and personality? Or are discoveries inevitable, and independent of the people who happen to be around to make them?

What if Darwin had toppled overboard before he joined the evolutionary dots? That discussion seems useful, because it raises interesting questions about the state of knowledge, then and now, and how it is communicated and portrayed. In his 2013 book Darwin Deleted — in which the young Charles is, indeed, lost in a storm — the historian Peter Bowler argued that the theory of evolution would have emerged just so, but with the pieces perhaps placed in a different order, and therefore less antagonistic to religious society.

In this week’s World View, another historian offers an alternative pathway for science: what if the ideas of Gregor Mendel on the inheritance of traits had been challenged more robustly and more successfully by a rival interpretation by the scientist W. F. R. Weldon? Gregory Radick argues that a twentieth-century genetics driven more by Weldon’s emphasis on environmental context would have weakened the dominance of the current misleading impression that nature always trumps nurture.

“Science without consensus would be chaos.”

Unusually for a historian, Radick has some experimental data to draw from. Over a term, students at the University of Leeds, UK, where Radick teaches, were presented with a curriculum that relegated Mendel to the margins and promoted Weldon in his place. The result, perhaps not surprisingly, was a class of undergraduates who were less willing to see genetics as immutable destiny.

Biologists may take issue with the methods, but the results seem less important than the fact that such an experiment could be performed at all. If the past is a foreign country, then it is also supposed to be one that cannot be revisited. With a little imagination, what other thought experiments could be tested in this way? The history of science is, after all, littered with major theories that became scientific orthodoxy but initially attracted a great deal of tough-minded criticism, from the Newtonian theory of universal gravitation to the Copenhagen interpretation of quantum mechanics.

These ‘winners’ became dominant before all the criticisms against them were fully answered, which raises questions about why the debates went the way they did, and whether they could have gone otherwise — and if so, with what repercussions.

A well-informed interest in alternative scientific pasts can help us to take the actual past more seriously as a source of present-day insight. It can also help us to stay self-critical as we make choices in the present. Science without consensus would be chaos. But the price of consensus is eternal vigilance against complacency, and a willingness to contemplate the road otherwise not travelled.

Journal name:
Nature
Volume:
533,
Pages:
291–292
Date published:
()
DOI:
doi:10.1038/533291b

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