In the sixties, British geo-chemist James Lovelock proposed that there couldn't be life as we know it on Mars because the amosphere there didn't have enough oxygen to sustain life. He assumed that the presence of living organisms that produce oxygen and carbon dioxide influences our atmosphere, and then took the idea a step forward. He proposed that living organisms might be able to act in concert to produce the type of atmosphere they need to survive.

Shortly afterward, a microbiologist called Lynn Margulis, in studying symbiotic relationships of microbes, suggested that organisms can evolve in a co-operative way to take on different tasks necessary to keep the collective colony alive...again, by modulating their environment so that the whole remains healthy. She called this theory endosymbiosis.

Together, the two formulated what has become known as the Gaia Hypothesis, first published in 1978. It's certainly still a hypothesis: a possible explanation of the facts that hasn't been conclusively proven or disproved. A decade later there was a world-wide scientific conference on it, and it still isn't disproved; but it's probably one of those things like God...it will never be adequately proven or disproved.

We have known for years that the human body is a miracle of positive and negative feedback loops that allow our enzymes and hormones to maintain the complex chemical environment in our bodies. What this means is that if any chemical, hormone, or protein becomes too high in our blood, it will block the release or synthesis of more of itself...similarly, a lack of one of these substances triggers a response to make more.

Lovelace and Margulis proposed that the Earth and all the living organisms in and on it act like a single huge organism; that each part and population contributes a function to the whole so that the biosphere is a self-regulating system. We have known for years that animals breathe in oxygen which allows their cells to pull energy out of foods and breathe out carbon dioxide as a waste product of this process...and the plants breathe in this carbon dioxide and use it to trap the sun's energy in the carbohydrates we then consume, and the waste product of this process is the oxygen we need to survive. But this same give and take appears to take place on much smaller levels as well. There are millions of strains of bacteria that help to modify the chemical environment, both in the organisms they live in and on the planet as a whole.

They took the idea a step forward and proposed that different populations of living things could be compared to the organs of a human body: the forests would be like the lungs of Gaia, breathing for Her; the waterways Her circulatory system, pumped by gravity as streams move downhill and by the gravitational pull of the Moon creating tides; the oceans with their wealth of micro-organisms that consume waste can be likened to the liver, which detoxifies.

This is certainly a theory that will appeal to pagans. For millenia the various pagan creation myths have seen the world as a female being who made Herself and all Her parts, and these myths anthropomorphise our world to be different parts of the body of a Goddess who is a larger, more powerful version of human. In fact, one of the arguments used by scientists who resist the Gaia Hypothesis is that it has too much emotional and spiritual appeal to be truly scientific.

Carrying on with the theme of attributing body functions to the populations of Gaia, the Hypothesis goes on to suggest that humans (and possibly other sentient beings) could be likened to Gaia's brain. The emotional appeal of this idea is obvious, but how well has Gaia's brain been doing, really?