Challenging the conventional wisdom is the way to make waves in science. - James Lovelock

The climate and the chemical properties of the Earth now and throughout its history seem always to have been optimal for life. For this to have happened by chance is as unlikely as to survive unscathed a drive blindfold through rush hour traffic.

We have since defined Gaia as a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet.

In Gaia, there's no such thing as pollution. The rules of the game are that any species that produces something noxious that affects the environment is doomed. Imagine there's some green bug … that decides it would be a neat trick to make chlorine. That bug is not going to succeed. If it doesn't kill itself off, it will certainly kill off its progeny, and destroy the environment around it and have no food to eat.