Gaia Theory

Daisyworld

Gaia Theory

James Lovelock’s Gaia Theory, which proposes that the entire system of organic life on Earth can be considered as a single ‘super-organism’, confused and outraged many scientists because it created problems for the mechanistic world-view that has dominated science since the early seventeenth century.

This paradigm, or imaginative picture of reality, sees the material world as essentially passive and dead. Like the mechanism of a clock, we can take the physical world apart, understand how the parts fit together and explain and predict its behaviour.

Living things were thought to be different, and until Darwin’s theory of evolution came along they were believed to be incontrovertible evidence of divine intervention in the world. Their structure, and their behaviour, had to be understood in terms of purpose – how they enabled the creature to survive and flourish – rather than by a causal mechanism.

Darwin’s theory of natural selection was, and is, seen by many as a brilliant insight which enabled science to get rid of the need to posit God as a supernatural agent to bring purposefulness into the world. Since only those mutations which act to enhance the survival of an organism will be preserved, there will be a progressive tendency for the structure of organisms to be adapted to the conditions in which they exist – as if they were designed with that in mind – and they will tend to behave as if they had an intention to survive and reproduce themselves.

If the Earth-system were really a super-organism – the conventional line goes – this would contradict evolution, because it clearly has not evolved by natural selection. So if it has the characteristics of adaptiveness and apparent purposefulness which define living organisms, then this would imply bringing back a mystical, religious idea of purpose being inherent in the universe – we would, in fact, have to bring God in to explain Gaia.

There is a clear fallacy in this line of argument – it is this: The argument assumes that natural selection is the only possible way for adaptiveness and purpose to come into being, other than a religious explanation in terms of a divine purpose. But no reasons have ever been given – nor could they be given – which would establish that natural selection is the only way this can occur. Natural selection is an answer to ‘natural theology’ because it is a sufficient condition for adaptivity and purposeful behaviour; no-one has ever shown that it is a necessary condition.

Therefore, the objection to Gaia Theory that it brings teleology into science without being based on natural selection is fallacious. If it can be shown that [quasi-] purposive behaviour can arise in nature in ways other than through natural selection, this objection has no force. And Lovelock and his collaborators have done just that, in an elegant series of thought-experiments and computer simulations collectively called ‘Daisyworld’.