A rethink of cause and effect could help when things get complicated

Some scientists insist that the cause of all things exists at the most fundamental level, even in systems as complex as brains and people. What if it isn’t so?

Life 25 May 2022

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Kyle Ellingson

THERE are seconds left on the clock, and the score is 0-0. Suddenly, a midfielder seizes possession and makes a perfect defence-splitting pass, before the striker slots the ball into the bottom corner to win the game. The moment will be scrutinised ad nauseam in the post-match analysis. But can anyone really say why the winners won?

One thing is for sure, precious few would attribute the victory to quantum mechanics. But isn’t that, in the end, all there is? A physicist might claim that to explain what happens to a football when it is kicked, the interactions of quantum particles are all you need. But they would admit that, as with many things we seek to understand, there is too much going on at the particle-level description to extract real understanding.

Identifying what causes what in complex systems is the aim of much of science. Although we have made amazing progress by breaking things down into ever smaller components, this “reductionist” approach has limits. From the role of genetics in disease to how brains produce consciousness, we often struggle to explain large-scale phenomena from microscale behaviour.

Now, some researchers are suggesting we should zoom out and look at the bigger picture. Having created a new way to measure causation, they claim that in many cases the causes of things are found at the more coarse-grained levels of a system. If they are right, this new approach could reveal fresh insights about biological systems and new ways to intervene – to prevent disease, say. It could even shed light on the contentious issue of free will, namely whether it exists. …

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