across the road. But there are also inherent questions and problems associated with being mobile. Do you become nomadic, of no fixed abode, or do you have a home that you return to each evening after a hard day running about chasing things? Either way there are pros and cons.
If you were a tunicate – a sea squirt – for example, you would have opted for an interim solution. The young sea squirt is a tadpole-like larva that possesses a primitive brain, which can be informed about what is going on by an organ of balance (such as we humans have in the middle ear), and a simple eye. It is equipped to navigate its way through changing aquatic conditions whilst engaged in a process of once-and-for-all house-hunting. When it finds its ideal home, the sea squirt gratefully settles down for life, and turns itself back into a plant by the simple expedient of eating its now redundant brain. (It has been suggested that this behaviour parallels that of university academics on finally obtaining a tenured appointment.)18 We might also note, to anticipate later discussions, that the issue of what to do with a brain that has evolved to a level of power that is out of all proportion to the current survival demands – when a species finds that, for a while, it has ‘got it made’ – is one that bears on the contemporary situation of homo sapiens. Eating a good chunk of the brain seems a solution to the problem that it might pay us to consider.
Sophistication and The
Proliferation of Needs, Part 1
The major components of the mammalian survival kit are sometimes (rather coarsely) referred to as the Four F’s – flight, fight, feed and mate – in approximately that order of urgency.19 If a predator appears, make yourself scarce. If you are cornered, or are trapped by the over-riding need to defend territory or young, stand your ground and see them off. When it is safe enough to do so, turn your energies back to the perennial search for sustenance. And if these other claims are assuaged for the moment, and the time is ripe, let your fancy lightly turn to thoughts of procreation. Each of these general departments ramified into elaborate rituals, and intricate signalling systems evolved to get these survival jobs done with the minimum of risk and inconvenience.
As the nervous system, and the body that it serves, grows in complexity, so the behavioural repertoire gets broader and subtler, and the sophistication with which different actions can be selected for different contingencies gets higher and higher. But at the same time, the vulnerability of the creature also increases. Sophistication aids survival, but it also calls into being new threats to survival. The more intricate a machine, the more ways there are in which it can break down. Choosing the evolutionary path of becoming high-tech means that the basic drive to survive and reproduce fragments into dozens of secondary and tertiary priorities.
For example, the more delicate your constitution, the more things there are that might upset you, or even kill you, if you ingest them by mistake. So your appetites, and sense of taste and smell, need to develop to provide an adequate level of protection. (And if you live in an environment that teems with chemicals that have not coevolved with you, and so there has not been the evolutionary time for knowledge of their risks and benefits to be incorporated into your preferences and aversions, you will be at risk, especially from those chemicals that are harmful in the long term – which decrease your fertility, for example – but which produce no short-term effect for you to learn from.)
If you have evolved a skeleton to support a big body, you are at risk from breaking bones. The more delicate your bits, the more carefully wrapped they have to be. If you developed a circulation system to carry oxygen to all those cells who work deep in the livermines, then they, and all the other underground workers, are at risk from any passing cloud of molecules that happen to bond more strongly to haemoglobin than oxygen does. If you grew lungs to get the oxygen into the right sort of contact with the blood, you can be beaten at your own game by a virus that makes the lung surface weep thick mucus, so that, like fish who drown when oil is spilt on the surface of their pond, you are disconnected from your vital power source.
If you have developed fast legs that enable you to outrun predators (rather than sharp teeth to see them off, and thick skin to minimize the danger of being punctured in a fight), you have to be able to see them coming, and are therefore vulnerable to twilight and cataracts. And if you have evolved an immunological secret police, who recognize and execute any enemies who have infiltrated the palace, you become all the more vulnerable when they go on strike, or worse, when they run amok and start attacking honest citizens (or each other).
Each new threat constitutes another priority that the system as a whole has to take into account in planning its next move. Any course of action is liable to disruption before it is complete. A snake may suddenly appear, or the urge to defecate slowly grow, and the response to each has to take into account the other priorities, the opportunities currently afforded by the world, and the range of available options for action. Should I stop chasing that gazelle and pay attention to the pain in my foot? Can I safely take a nap here, or should I wait till I get home? Am I likely to find a familiar snack on the way, or should I eat these berries now, even though they taste a bit funny? The more diverse your portfolio of requirements, the more you need a brain to keep track of them all; to register the competing claims for attention and action, and come up with a good guess as to what the system as a whole is best advised to do next.
Neural Webs
The brain is a focus for the co-ordinating aspect of the body, just as the intestines are the main centre for digestion, or the legs of locomotion. But if you want to understand digestion or locomotion fully, you will have to take a systems view, and understand the role of the jaws, and of exercise, in digestion; or of the lungs and the spine in mobility. Just so, the brain plays a central part in integrating processes but the processes are themselves essentially bodily. ‘Mind’ is an aspect of an animal that is distributed throughout the body even though some facets of ‘mind’ are most closely associated with the nervous system. The unit of intelligence of an animal is its body, not its brain, just as the unit of ‘music-making’ is the orchestra, not the conductor. If the orchestra is big, and the music intricate, the conductor’s role is all the more important. But he never transcends his role as a valued member and servant of the musical collective. He never becomes a dictator.20
For example the immune system is usually discussed in relative isolation from the CNS. However, some interesting recent research has revealed how ‘brain-like’ the immune system actually is, and has explored the ways in which CNS and immune system continually talk to each other. A class of messenger molecules from the peptide family has been shown by Candace Pert and others to mediate between the neural and immune systems, and thereby to co-ordinate, and effectively integrate, them. She goes so far as to say that: ‘White blood cells are bits of brain floating around the body.’21 Francisco Varela has referred to the immune system in a recent paper as ‘the second brain’, and has argued that the secret handshakes that enable the antibodies to recognize ‘friend’ from ‘foe’ also act as the basis for the body’s overall sense of identity. The immune system, like the CNS, is primarily a communication system, he argues; one which subserves the vital bodily feeling of ‘family’.22
By taking an evolutionary perspective, we are forcibly reminded of the extent to which intelligence is a bodily, not purely (or even mainly) a mental, phenomenon. And just as most of the workings of the body are ‘dark’ to us, beyond the reach of conscious introspection, so we may begin to open up the question of how much of what we have thought of as our ‘intelligence’, our ‘cognition’, is also inaccessible to the conscious mind. Perhaps intelligence does not reside in consciousness. Perhaps consciousness no more shows us the workings of the mind than a television picture shows us the workings of the television.
Plastic Brains
No amount of genetic adaptation can prepare you for the unpredictable. The world is always liable to change