EVOLUTION'S FOUR DIMENSIONS

The life of any animal is composed of a string of sensations, followed by responses. The blue whale hears the booming songs of its fellows, and swims half an ocean to rejoin them. Finding a clump of tender bamboos, a panda ambles over and grabs the choicest shoots to eat. How does an animal respond appropriately to its sensations? By using its mind. That is what mind is for; that is why mind evolved.

We are going to consider evolution primarily as a development of mind, of consciousness. You will be able to follow the account most clearly if you recognise that there are four strands or dimensions of evolution: three relate to lower evolution,  and higher evolution is the fourth. As well as the lower evolution of minds, there has been, of course, a biological evolution of the physical form of animals. The third dimension of lower evolution is culture -- a gradual advance in the sophistication of social traditions, patterns of behaviour learnt and passed on down the generations.

Culture is not unique to human beings. Many social animals develop cultures. The learnt local song dialects in some species of birds, for instance, and cultural forms in animals and humans, evolve over time. Animals had to evolve a certain mental sophistication before they could create cultures; they had to be able to learn patterns of traditional behaviour. So cultural evolution depends on how far consciousness has evolved. In turn, some cultural contexts can stimulate the further evolution of consciousness; for example, as soon as early humans learnt to speak (a cultural form), they had a new tool, language, for exploring their own experience, and self-awareness became more of a possibility.

The mental and cultural are not the only strands of evolution to interact. Most obvious is the way biological evolution influences all the other three dimensions. For example, you cannot speak unless you can control sounds with structures like a voice box, tongue, and lips. You cannot think very well without a large and complex brain.

At first sight, one might not expect there to be any influences on biological evolution from the other dimensions, but, remarkably, there are. We shall see that animal behaviours that become long-lasting traditions can completely alter the course of evolution. They can create quite new environments, in which new varieties of animal will tend to evolve; in these cases, it is a matter of a culture guiding the genes to produce a new species. And where do behaviours come from? The mind. A rabbit bolts when someone comes near because the complex of sensations that enter its mind `means' danger to it, and its pattern of responses, inborn and learnt, culminate in flight. It can learn, again via its mind, to become tamer. Occasionally, its evolving mind might come up with a new response, subtly altering the options available to rabbits.

(Continued on page 10)

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