What Is Life? by Paul Nurse

Author:Paul Nurse
Language: eng
Format: epub
Publisher: David Fickling Books Ltd
Published: 2020-09-15T00:00:00+00:00

5. LIFE AS INFORMATION

Working as a Whole

What was it that made that yellow butterfly venture into my childhood garden all those years ago? Was it hungry, looking for somewhere to lay its eggs, or perhaps being chased by a bird? Or was it just responding to some inbuilt urge to explore its world? Of course I do not know why that butterfly was behaving as it did, but what I can say is that it was interacting with its world and then taking action. And to do that, it had to manage information.

Information is at the centre of the butterfly’s existence and indeed at the centre of all life. For living organisms to work effectively as complex, organized systems they need to constantly collect and use information about both the outer world they live in and their internal states within. When these worlds – either outer or inner – change, organisms need ways to detect those changes and respond. If they do not, their futures might turn out to be rather brief.

How does this apply to the butterfly? When it was flying about, its senses were building up a detailed picture of my garden. Its eyes were detecting light; its antennae were sampling molecules of the different chemical substances in its vicinity; and its hairs were monitoring vibrations in the air. Altogether, it was gathering a lot of information about the garden I was sitting in. It then brought all this diverse information together, with the aim of transforming it into useful knowledge that it could then act upon. That knowledge might have been detecting the shadow of a bird or of an inquisitive child, or recognizing the smell of nectar from a flower. This then generated an outcome: an ordered sequence of wing movements that led the butterfly to either avoid the bird or to settle on a flower to feed. The butterfly was combining many different sources of information and using them to make decisions with meaningful consequences for its future.

Closely linked with their reliance on information is the way living things act with a sense of purpose. The information the butterfly was gathering meant something. It was being used by the butterfly to help it decide what to do next to achieve some specific end. That meant it was acting with purpose.

Biology is a branch of science where it can often make sense to talk about purpose. In the physical sciences by contrast we would not ask about the purpose of a river, a comet or a gravitational wave. But it does make sense to ask that of the cdc2 gene in yeast, or of the flight of a butterfly. All living organisms maintain and organize themselves, they grow, and they reproduce. These are purposeful behaviours that have evolved because they improve the chances of living things achieving their fundamental purpose, which is to perpetuate themselves and their progeny.

Purposeful behaviour is one of life’s defining features, but it is only possible if living systems operate as a whole.

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