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Stewart Brand majored in biology at Stanford, where his teacher was Paul Ehrlich, a population biologist. Ehrlich too was fascinated by the rubbery chameleon-on-the-mirror paradox. He saw it most vividly in the relationship between a butterfly and its host plant. Fanatical butterfly collectors had long ago figured out that the best way to get perfect specimens was to encase a caterpillar, along with a plant it feeds on, in a box while waiting for the larvae to metamorphose. After transformation, the butterfly would emerge in the box sporting flawless unworn wings. It would be immediately killed and mounted.

This method required that collectors figure out which plants butterflies ate. With the prospect of perfect specimens, they did this thoroughly. The result was a rich literature of plant/butterfly communities, whose summary indicated that many butterflies in the larvae stage chomp on only one specific plant. Monarch caterpillars, for instance, devour only milkweeds. And, it seemed, the milkweed invited only the monarch to dine on it.

Ehrlich noticed that in this sense the butterfly was reflected in the plant, and the plant was reflected in the butterfly. Every step the milkweed took to keep the monarch larvae at bay so the worm wouldn't devour it completely, forced the monarch to "change colors" and devise a way to circumvent the plant's defenses. The mutual reflections became a dance of two chameleons belly to belly. In defending itself so thoroughly against the monarch, the milkweed became inseparable from the butterfly. And vice versa. Any long-term antagonistic relationship seemed to harbor this kind of codependency. In 1952, W. Ross Ashby, a cybernetician interested in how machines could learn, wrote, "[An organism's gene-pattern] does not specify in detail how a kitten shall catch a mouse, but provides a learning mechanism and a tendency to play, so that it is the mouse which teaches the kitten the finer points of how to catch mice."

Ehrlich came across a word to describe this tightly coupled dance in the title of a 1958 paper by C. J. Mode in the journal Evolution. It was called "coevolution," as in "A mathematical model for the co-evolution of obligate parasites and their hosts." Like most biological observations, the notion of coevolution was not new. The amazing Darwin himself wrote of "coadaptions of organic beings to each other..." in his 1859 masterpiece Origin of Species.

The formal definition of coevolution runs something like this: "Coevolution is reciprocal evolutionary change in interacting species," says John Thompson in Interaction and Coevolution. But what actually happens is more like a tango. The milkweed and monarch, shoulder to shoulder, lock into a single system, an evolution toward and with each other. Every step of coevolutionary advance winds the two antagonists more inseparably, until each is wholly dependent on the other's antagonism. The two become one. Biochemist James Lovelock writes of this embrace, "The evolution of a species is inseparable from the evolution of its environment. The two processes are tightly coupled as a single indivisible process."

Brand picked up the term and launched a magazine called CoEvolution Quarterly. It was devoted to the larger notion of all things -- biological, societal, and technological -- adapting to and creating each other, and at the same time weaving into one whole system. As an introduction Brand penned a definition: "Evolution is adapting to meet one's needs. Coevolution, the larger view, is adapting to meet each other's needs."

The "co" in coevolution is the mark of the future. In spite of complaints about the steady demise of interpersonal relationships, the lives of modern people are increasingly more codependent than ever. All politics these days means global politics and global politics means copolitics. The new online communities built between the spaces of communication networks are coworlds. Marshall McLuhan was not quite right. We are not hammering together a cozy global village. We are weaving together a crowded global hive -- a coworld of utmost sociality and mirrorlike reciprocation. In this environment, all evolution, including the evolution of manufactured entities, is coevolution. Nothing changes without also moving closer to its changing neighbors.

Nature is chock-a-block with coevolution. Every green corner sports parasites, symbionts, and tightly coupled dances. Biologist P. W. Price estimated that over 50 percent of today's species are parasitic. (The figure has risen from the deep paleologic past and is expected to keep rising.) Here's news: half of the living world is codependent! Business consultants commonly warn their clients against becoming a symbiont company dependent upon a single customer-company, or a single supplier. But many do, and as far as I can tell, live profitable lives, no shorter on average than other companies. The surge of alliance-making in the 1990s among large corporations -- particularly among those in the information and network industries -- is another facet of an increasing coevolutionary economic world. Rather than eat or compete with a competitor, the two form an alliance -- a symbiosis.

The parties in a symbiosis don't have to be symmetrical or even at parity. In fact, biologists have found that almost all symbiotic alliances in nature entail a greater advantage for one party -- in effect some hint of parasitism -- in every codependency. But even though one side gains at the expense of the other, both sides gain over all, and so the pact continues.

In his magazine CoEvolution Brand began collecting stories of coevolutionary games. One of the most illustrative examples of alliance making in nature is the following:

In eastern Mexico live a variety of acacia shrubs and marauding ants. Most acacias have thorns, bitter leaves, and other protection against a hungry world. One, the "swollen thorn acacia," learned to encourage a species of ant to monopolize it as a food source and kill or run off all other predators. Enticements gradually included nifty water-proof swollen thorns to live in, handy nectar fountains, and special ant-food buds at the leaf tips. The ants, whose interests increasingly coincided with the acacia's, learned to inhabit the thorns, patrol the acacia day and night, attack every acacia-hungry organism, and even prune away invading plants such as vines and tree seedlings that might shade Mother Acacia. The acacia gave up its bitter leaves, sharp thorns, and other devices and now requires the acacia-ant for survival. And the ant colonies can no longer live without the acacia. Together they're unbeatable.

In evolutionary time, the instances of coevolution have increased as sociability in life has increased. The more copious life's social behaviors are, the more likely they are to be subverted into mutually beneficial interactions. The more mutually responsive we construct our economic and material world, the more coevolutionary games we'll see.

Parasitic behavior itself is a new territory for organisms to make a living in. Thus we find parasites upon parasites. Ecologist John Thompson notes that "just as the richness of social behaviors may increase mutualism with other species, so may some mutualisms allow for the evolution of new social behaviors." In true coevolutionary fashion, coevolution breeds coevolution.

A billion years from now life on Earth may be primarily social, and stuffed with parasites and symbionts; and the world economy may be primarily a crowded network of alliances. What happens, then, when coevolution saturates a complete planet? What does a sphere of reflecting, responsive, coadapting, and recursive bits of life looping back upon itself do?

The butterfly and the milkweed constantly dance around each other, and by this ceaseless crazed ballet they move far beyond the forms they would have if they were at peace with each other. The chameleon on the mirror flipping without rest slips into some deranged state far from sanity. There is a sort of madness in pursuing self-reflections, that same madness we sensed in the nuclear arms race of post-World War II. Coevolution moves things to the absurd. The butterfly and the milkweed, although competitors in a way, cannot live apart. Paul Ehrlich sees coevolution pushing two competitors into "obligate cooperation." He wrote, "It's against the interests of either predator or prey to eliminate the enemy." That is clearly irrational, yet that is clearly a force that drives nature.

When a human mind goes off the deep end and gets stuck in the spiral of watching itself watching a mirror, or becomes so dependent upon its enemies that it apes them, then we declare it insane. Yet there is a touch of insanity -- a touch of the off-balance -- in intelligence and consciousness itself. To some extent a mind, even a primitive mind, must watch itself. Must any consciousness stare at its own navel?

This was the point in the conversation when Stewart Brand pointed out to Gregory Bateson his fine riddle of the chameleon on the mirror, and the two biologists swerved to follow it. The chase arrives at the odd conclusion that consciousness, life, intelligence, coevolution are off-balanced, unexpected, even unreasonable, given the resting point of everything else. We find intelligence and life spooky because they maintain a precarious state far from equilibrium. Compared to the rest of the universe, intelligence and consciousness and life are stable instabilities.

They are held together, poised upright like a pencil standing on its point, by the recursive dynamics of coevolution. The butterfly pushes the milkweed, and the milkweed pushes the butterfly, and the harder they push the more impossible it becomes for them to let go, until the whole butterfly/milkweed thing emerges as its own being -- a living insect/plant system-pulling itself up by its bootstraps.

Rabid mutualism doesn't just happen in pairs. Threesomes can meld into an emergent, coevolutionarily wired symbiosis. Whole communities can be coevolutionary. In fact, any organism that adapts to organisms around it will act as an indirect coevolutionary agent to some degree. Since all organisms adapt that means all organisms in an ecosystem partake in a continuum of coevolution, from direct symbiosis to indirect mutual influence. The force of coevolutionism flows from one creature to its most intimate neighbors, and then ripples out in fainter waves until it immeasurably touches all living organisms. In this way the loose network of a billion species on this home planet are knit together so that unraveling the coevolutionary fabric becomes impossible, and the parts elevate themselves into some aggregate state of spooky, stable instability.

The network of life on Earth, like all distributed being, transcends the life of its ingredients. But bully life reaches deeper and ties up the entire planet in the web of its network, also roping in the nonliving matrix of rock and gas into its coevolutionary antics.