Mary Midgley   (Published in The Guardian, 2001)

The idea of Gaia - of life on earth as a self-sustaining natural system - is not just some strange Californian fancy. It is a central concept for our age, a tool that can help with many of our current problems. It does not just make possible new applications of science and technology. It can also counteract the corrosive forms of social atomism that colour much current scientific and political thought. Once fully grasped, it makes a deep difference, not just to how we see the earth, but also to how we understand life and ourselves.
Most of the difficulty about grasping the concept of Gaia is not scientific. Earth-scientists, after initial delays and puzzlements, have largely accepted the core of its message. They are using the Gaian paradigm regularly in current thinking, even though they are not yet fully accustomed to it and are still nervous about using the name. That late and much-lamented great biologist W.D.Hamilton compared the acceptance of Gaian thought to the Copernican revolution, which (as he pointed out) also took some time to be fully understood. But the recent Amsterdam Declaration, issued by a number of international bodies working on climate change, is typical in stating, as a matter of plain fact, 'The Earth System behaves as a single, self-regulating system'.
The real difficulty about the concept of Gaia lies in fitting it into the fragmented framework of our thought about the earth and our own place on it. This thought is today increasingly specialized. It is riven by a great gap between traditions in the earth-sciences and the life-sciences, and, beyond that, by the gap that Descartes made between our ideas about mind and body.
Though we spend a lot of our time dealing with our bodies, we still tend, in handling the outer world, to conceive of ourselves simply as minds - intelligent beings - observers and controllers, manipulating an indefinite mass of alien matter for our own convenience. We tend to see the earth as simply part of that alien matter. We do not feel like small, dependent parts of a vast and vulnerable system, parts who can do little to control it and who had better not get in the way of its complex workings more than we can help.
The trouble is that our moral, psychological and political ideas have all been armed against holism - against looking for an enclosing context that will relate the various parts of a problem. Faced by a leaf, our tendency is to start enquiries by grinding it up and putting the bits in a centrifuge rather than by asking about the tree and the forest in which it grew. Similarly, when we think about ourselves, we tend to do so in isolation. We get trapped in the narrow, atomistic, seventeenth-century image of social life that grounds today's crude and arid individualism. A more realistic view of the co-operative earth can give us a more realistic view of ourselves as its inhabitants.
This matters. Our ideas about our place in the world pervade all our thought, along with the imagery that expresses them. They constantly determine what questions we can ask and what answers to them will seem possible. They enter into all our decision-making. Twists in this imagery surely account for the strange difficulty that we still have in taking the environmental crisis quite seriously - in grasping its proper place in our scheme of priorities.
Thus, President Bush clearly does not feel at all embarrassed in explaining that his country cannot co-operate with others to resist global warming because such efforts might clash with its commercial interests. It strikes him as quite natural to insist that he need take no notice of the steerage passengers who are reporting that the ship is sinking. He repeats that it is not sinking at his end. Accordingly, their chatter must not be allowed to disturb important discussions about the redecoration of the first-class lounge.

Every influential thought-system has at its core a guiding myth, an imaginative vision addressed to the deeper needs of our nature. Through most of the twentieth century, prophets in the West, from Freud and J-P Sartre to Ayn Rand and Margaret Thatcher, have mostly painted the world in individualistic terms, assuming that individual freedom and self-development are the only unquestionable values. We hardly use the notion of sacredness today except in a single context - `the sanctity of human life'. Indeed, describing anything else as sacred can cause embarrassment.
This emphasis on the value of the individual has, of course, been a priceless element in our culture. Of course we must preserve it. Yet, when it becomes exclusive - when it shuts out other values - it gets gravely distorted and begins to lose its meaning. Human beings, like leaves, grow in a context. They need to value that context as well as their own peculiarity. And that context does not only consist of the other human beings around them. It includes the non-human world as well.
The Enlightenment has accustomed us to thinking of that world as existing mainly as a means to human ends, because it has always stressed the pattern of the social contract. Individualism tells us that the answer to the question `Why should I bother about this?' is always, `It will pay you because of the contract which gives you your entrance-ticket to society'.
That thought is often useful for disputes with fellow-citizens. But when we are dealing with such chronic non-litigants as the rain-forest and the Antarctic, this answer falters. They are not citizens. They never signed a contract. They know nothing of us. If all duties are contractual, how can we possibly have duties to them? John Rawls raised this question as an afterthought at the end of his famous book A Theory of Justice. He could only say that it lay outside his contractual theory of morals and that somebody ought to investigate it one day. But the real response surely has to be, `you shouldn't have started from here'.
In spite of much recent propaganda, we are not really Rawlsians. Contracts only explain a small part of our duties, even to our fellow-humans, and in a non-human perspective they do not help at all. Direct concern about the destruction of the natural world is still a natural, spontaneous feeling with us, and one that we no longer have reason to suppress. We now know - as Descartes did not - that we are closely akin to a whole continuum of other life forms, out of which we have evolved. We are not pure intellects, sent from a remote intellectual sphere to exploit and colonise the planet. We belong here. Except for a few deluded space-fantasists, we know that we could not possibly live anywhere else. This is our only home.
On this point the findings of modern science agree much better with the attitude of supposedly primitive cultures, in which people do see themselves as part of the whole spectrum of life around them, than they do with the twentieth century's exclusive humanism. Perhaps it might pay us to complete our Copernican revolution - to start taking the way the earth works a bit more seriously.