The Gaia hypothesis, now accorded the status of Gaia theory, is maturing with experience and the tests of time, not unlike the humans of this book. It is spurring a great deal of scientific research into the geophysiology of our living planet. It is also spurring philosophic conceptions of what it means to our species to be part of a living planet. Some of these conceptions stay carefully within the accepted limits of science; others have a religious bent. Most, especially environmentalist conceptions, advocate for humanity, being primarily concerned with human survival. A few, taking a clue from my partner Lynn Margulis and myself, advocate for the planet and the much maligned microbes with which the Gaian system originated and which continue to do its basic work.

Elisabet Sahtouris' conception integrates scientific Gaian evolution with the human search to connect with our roots, inspiring us to learn from billions of years of Gaian experience in the self-organization of workable living systems. It is well balanced between advocacy for the planet and advocacy for humans, placing the onus on humans to recognize the lack of maturity involved in believing we can manage the planet, and to learn instead to follow its lead in organizing ourselves.

Elisabet gives us valuable insights as she draws parallels between the evolution of cells and the evolution of human society, pointing out the contrast between the healthy organization of cells, bodies, and biosystems on the one hand and the unhealthy organization of economics and politics in human society on the other. While she argues that our social evolution is not as much under our control as we like to think, she warns us that our survival depends on our meeting the evolutionary demand to transform competitive exploitation into cooperative synergy.

On the whole, her advice makes sense because she herself has taken the trouble to learn directly from nature as well as from the growing store of scientific knowledge about nature. I began the preface to my own book The Ages of Gaia by saying that the place in which it was written was relevant to its understanding. Living and working in the Devonshire countryside, far from universities and large research organizations, makes me an eccentric as a scientist, but, as I said, it is the only way to work on an unconventional topic such as Gaia. When I met Elisabet, having accepted her invitation to trace Gaia's roots in Greece, I recognized her as a kindred spirit. She had abandoned academia for a simple lifestyle in the kind of natural setting that brings one closer to understanding what our planet and our species are all about; she was free to develop her own conception of Gaia through a synthesis of scientific knowledge and personal experience of nature. To my surprise, she expressed some concern, some guilt, at having abandoned her profession of science for a pleasant existence in a forest overlooking the sea, the kind of forest that had been home to her in childhood, where she could work out the meaning of things for herself. As I read her work in progress, I was able to assure her she could never have done anything comparable in a constrained academic setting.

In the intervening years, even in the short time since I wrote my own words about Gaia being an unconventional topic, less eccentric scientists than I have declared Gaia more conventional, meaning that Gaia theory is now recognized as a legitimate and fruitful basis for scientific investigation and is thus being brought into the scientific fold. In our first account of Gaia as a system neither Lynn Margulis nor I fully understood what it was we were describing. Our language tended to be anthropomorphic and, especially in my first book, Gaia, poetic. Not surprisingly, some scientists misunderstood our intentions, but over time we developed a clearer version, which became Gaia theory. This theory sees the evolution of the material environment and the evolution of organisms as tightly coupled into a single and indivisible process or domain. Gaia, with its capacity for homeostasis, is an emergent property of this domain.

As the title of one article in Science put it, "No Longer Willful, Gaia Becomes Respectable." This means that Gaia scientists are constrained by bureaucratic forces, by the pressures of tenure, and by the tribal divisions and rules of scientific disciplines. That, in turn, means we need some antidote to the inevitable separations and constraints. We need independent synthesizers and visionaries who can make sense of the data produced by the scientific establishment and present it to us in ways that make our living planet real to us within the Gaian context and thus give meaning to our own lives and those of our children and grandchildren.

This is what Elisabet Sahtouris' work means to me, for she comfortably integrates the traditionally separated domains of biology, geology, and atmospheric science to show us the evolution of our living planet and our own roots within it. She then inspires us on ethical grounds to learn from this planetary organism of which we are part, showing us how we can mature as a species well integrated into the larger dance of life.

Elisabet uses the metaphor of dance effectively for its concepts of improvisation and evolution, the creation of order from chaos, the myriad patterns that can be created from a few basic steps. I am myself an inventor of scientific instruments, and so it is second nature to me to think in terms of mechanical and mathematical models. Cybernetic models have proved especially useful in my work of demonstrating how Gaian homeostasis, such as maintaining the Earth's temperature, might work. Yet I quite agree with Elisabet that any model we make of nature is at heart metaphorical in that it begins with some image or formula familiar to us humans and used to represent the complexities of nature in simple, understandable, and useful ways. No metaphor should be mistaken for reality, and perhaps a variety of metaphors is insurance against the temptation to do so. I am increasingly impressed by scientists and philosophers who find non-mechanical metaphors for natural systems useful in interpreting Gaia theory.

Elisabet's analysis of science reflects a trend that may well make science in the near future as unrecognizable as today's science would be to the ancients. She does well to remind us that science is a human activity that evolves, a living system in which conservatism should be balanced by healthy controversy. After all, as she so well describes, all Gaian systems are forever busy working out their cooperation through conflicting interests, their unities through diversity.

The optimistic view this book radiates, that despite our errors and immaturities we can still become a healthy species within a healthy planet, is much needed in this age of doomsday predictions. Though time is growing short in our continued destruction of forests, atmospheres, and other critical Gaian systems, nothing would make me happier personally than to see Gaia theory useful in bringing about a better world for Gaia and her people.

-James E. Lovelock