Consciousness and EvolutionComment on this article?
A metaphysical view of the place of consciousness?There's a metaphysical or mystical view of consciousness that is deeply attractive to many people who want to combine a scientific world outlook with a spiritual one. It was certainly attractive to me when, about 30 years ago, I wrote two books on the subject, at a time when I was much influenced by Indian philosophy.
In outline, it goes like this. Life originated on this planet in very simple forms, perhaps even simpler than present-day bacteria. Then came many-celled organisms; at first these, too, were simple, but with gradually increasing size and complexity there came the need for a nervous system to coordinate functioning. To start with this was just a network of nerve cells, but later there developed a nervous system headquarters which entailed yet another level of organization; this was the primitive brain. As animals became still more complex, the brain began to differentiate to provide a number of levels of organization. Finally, the human brain appeared, capable for the first time of generating self-awareness.
You may say there's nothing metaphysical about this scenario, and you'd be right. It implies that consciousness is an emergent property, which is what most people with a scientific background tend to believe. That is, as brains became more complex, they gradually allowed for greater and greater degrees of awareness, until, at the human level, language, abstract thought, and art became possible. Nothing metaphysical there.
But what is the nature of this self-awareness? What is consciousness? Here we get into deep philosophical water. We encounter what David Chalmers calls the Hard Question. Some philosophers think it is indeed so hard that we cannot hope to solve it, while others cut the Gordian knot by saying that the mind-body problem is illusory, a pseudo-problem, that can be made to disappear if we analyse it correctly.
Consciousness an evolutionary phenomenonWhatever position they take about the problem, however, modern philosophers generally assume that for billions of years on earth there were no minds, because there were no nervous systems, and even when nervous systems did appear they were for a long time too primitive, too simple, to sustain anything we would call a mind. Eventually mind did arise, but there is no agreement about how far back in evolutionary time we have to go to find its beginnings Equally, there is no agreement about whether any living creatures have minds apart from ourselves. Are dogs, cats, chimpanzees, dolphins conscious? Is language necessary for consciousness to exist?
The role of God?Such questions are notoriously hard to answer, but religious people may say that they become easier if we bring God into the picture. God Himself is supposed to be the Supreme Mind, so consciousness, the theist believes, is a gift from God, something that is added to the physical organism; in fact, it's the soul. This implies dualism, the idea that mind or body are separate, which is unacceptable to almost all modern brain scientists, but it's difficult to avoid it if you are a Christian. (Many New Age enthusiasts go even further and support a triune constitution for human beings, alleging that we are made up of body, mind, and spirit.)
The question whether animals are conscious then becomes whether they have souls. Descartes, as we know, thought that they didn't, and were therefore automata, but not all subsequent Christian theologians have agreed with him. In any case, whatever creationists may say, religious ideas, including the existence of the soul, are not necessarily in conflict with evolution.
Catholics and evolutionDuring my Catholic upbringing I was told that there was no reason why Catholics should not accept Darwinism, including the view that Man was descended from apes; it was only necessary to believe that at some point God infused a soul into one (just one) of our forebears: a sort of simian Adam. It was not explicitly stated that the arrival of this soul made the ape conscious in the full sense of the word, but certainly one could understand the idea like that.
I ceased to believe in Christianity in my twenties but I continued to puzzle about consciousness, mind, and free will. I still wanted to believe in the possibility of survival of physical death, but how could this be reconciled with the apparently one-sided dependence of consciousness on the brain? When, later, I became a medical student, this dilemma grew ever starker as I learned more about our dependence on the brain. Later still, when I came into contact with Indian philosophy and metaphysics, I thought I'd been given the solution to the mystery. It seemed beautifully simple.
Does the brain transmit consciousness like a radio?The solution was to hold that consciousness is not created anew for each individual, as the soul doctrine implies. Instead, consciousness is eternal and omnipresent, but can only be detected provided there is a suitable receiver. This receiver, of course, is the brain. It doesn't generate consciousness, as rationalists suppose, it simply reflects it.
As an analogy, consider the electromagnetic waves that surround us, carrying sound and vision. We can't hear or see these waves, but we can detect them if we have suitable apparatus. An old-fashioned crystal set will pick up radio broadcasts, but rather faintly and not very clearly. A valve radio (if any are left outside museums) will do better, but the sound is still not as good as it is with a modern transistor radio, especially if it is using frequency modulation. More complex receivers can produce pictures as well as sounds. All the information is out there, waiting for us; whether, and how well, we can detect it depends on the quality of our receivers.
Brains, likewise, vary in their ability to detect consciousness. Some give imperfect or partial renderings of what's available, while others are much more sensitive. The stated aim of certain spiritual disciplines is to tune the system ever more finely so that it becomes a better instrument for its true purpose, which is the reflection of the omnipresent Divine Consciousness. (In the Vedanta philosophy, our consciousness is ultimately found to be identical with God.)
Although the human brain is the most sophisticated and sensitive detector of consciousness we know of, the argument continues, there is in principle no limit to how far down the chain of organization we can go before consciousness fades right out. Not only mammals and birds, but reptiles, fish, and even insects can be thought of as reflecting consciousness, though perhaps to only a minute degree for some of them. Must we stop there? Is a nervous system really necessary? What about plants? And bacteria? And if they, too, have their tiny glimmer of consciousness, shall we deny it to rocks, crystals, molecules, atoms, elementary particles? Just where do we draw the line? Perhaps we can't draw it at all, in which case we arrive at panpsychism: Mind, or Spirit, is in everything.
Mystical approaches to consciousnessMany mystics, especially in the East, have indeed drawn just this conclusion. The Sufi Jalal-al-Din Rumi said: "I was a mineral; I died to the world of minerals and became a vegetable; I died to the world of vegetables and became an animal; I died to the world of animals and became a man." But it isn't only Eastern mystics who have thought in this way; so, too, have some modern Western intellectuals, even including scientists.
Schrodinger's theoryIn Mind and Matter the physicist Erwin Schrodinger wrote: "I should say the overall number of minds is just one... But I grant that our language is not adequate to express this, and I also grant, should anyone wish to state it, that I am now talking religion, not science--a religion, however, not opposed to science, but supported by what disinterested science has brought to the fore."(p.145). It's possible that, in saying this, Schrodinger was influenced by German nineteenth-century Idealism.
I quoted this passage from Schrodinger in one of the books I wrote about these ideas in the 1970s because it accorded perfectly with what I was thinking at the time. In the Vedanta system of India, which I was then following, everything in the world, including us, is a manifestation of this underlying consciousness, and spiritual enlightenment consists in perceiving directly that consciousness and the world are really one. (For a good modern exposition of this idea, see Peter Russell, From Science to God: The Mystery of Consciousness and the Meaning of Light.) The meditation method I was using was supposed to bring about this ultimate realization.
It was an intoxicating idea, not least because it seemed to me, as it did to Schrodinger, to provide a way of reconciling spirituality with science, and I remained under its spell for a good many years. Indeed, I can still feel its attraction today, but I no longer find it persuasive in the way I once did. And what I should like to do in this essay is to explain where I think the difficulty lies.
Consciousness and the Great Chain of BeingIn the Middle Ages it was widely believed that all living creatures could be arranged in a kind of ranking order of perfection called the Great Chain of Being. In the West this idea goes back to Plato, and it was later incorporated into Christianity. Genesis in the Old Testament supports it. Man is supposed to be dominant over the rest of creation, but above him there are the ordered ranks of angels and, above them again, the Ultimate Perfection, who is of course God. This is essentially a static picture of the universe, in which everyone knows their place; it has been called the Ladder of Perfection. Similar ideas are found in Gnosticism and its many offshoots, in Sufi and Ismaili mysticism within Islam, and in mediaeval Judaism.
It wasn't only the living creation that was supposed to have this hierarchical character; so, too, did the physical universe. The Earth (with Hell at its core) was at the centre, and was surrounded by the various spheres of the Ptolemaic cosmos that carried the Moon, Sun, planets, and fixed stars on concentric spheres. The hostility of the Church to the Copernican scheme, in which the Earth became simply another planet revolving round the Sun, was due not only to the fact that it contradicted Scripture but also to the threat it posed to the stability of the mediaeval universe. Thus, the churchmen who condemned Galileo were not mistaken in their own terms; they were right to be alarmed.
Shattering the ChainIn the end, of course, the Church had to accommodate the Copernican version of cosmology and accept that the earth revolves round the sun; it could do nothing else. But an even greater challenge to religious orthodoxy occurred in 1859, when Charles Darwin published his Origin of Species. The challenge didn't arise only from the claim that Man was descended from the apes, even though this may have been what chiefly exercised the minds of Darwin's contemporaries; as we have seen, the Catholic Church, at least, was able to come to terms with that. What Christianity couldn't and still can't come to terms with is the view that there is no underlying plan or purpose in evolution. The implication of Darwin's theory of natural selection is that no designer is needed; natural selection (plus sexual selection) can do the job without outside help.
But is the Chain really shattered?It might seem that the myth of the Great Chain of Being was finally shattered by Darwin, but some links still encumber our thinking today, at least at the popular level. For instance, it's still quite common to come across cartoon depictions of human evolution which begin at the left side of the page with a monkey; next comes a knuckle-walking ape; then a semi-erect beetle-browed figure, representing Homo erectus; next, probably, another rather taller and more erect, but still hunched and beetle-browed, individual, labelled Neanderthal Man; and finally, and triumphantly, Modern Man, with his well-developed chin and noble brow. (This last member of the sequence is nearly always recognizably European.)
Human evolution as a hero mythIt has also been remarked that the story of human evolution is often cast in the myth of the hero. Man comes down from the trees, learns to walk upright, masters fire, discovers agriculture, invents technology, conquers the world. Man is thus represented as the culmination of a series, a presumably inevitable trend towards increasing intelligence via a sequence leading to perfection.
Darwin himself didn't think of evolution as a ladder, even though he occasionally made remarks which might suggest that he did. The appropriate metaphor for his view of how species become differentiated is a bush: multiple branches going off in all directions, and this is still the modern scientific conception of how evolution works. But the idea of a ladder remains pretty firmly lodged in the popular imagination, because it is intuitively so appealing; it even appears in some modern textbooks, and it's still quite common to come across references to `higher' and `lower' mammals in scientific papers.
Is there an inevitable trend towards intelligence?For people who, like me in the 1970s, wanted to find common ground between evolution and spirituality, it was axiomatic that there must be a trend towards increasing intelligence during the course of evolution. Our whole argument depended on it. Whatever the exact sequence of events might have been, it was essential for us to suppose that reaching awareness was in some sense the goal of evolution. Looking back on my thinking at the time, I find it surprising that I didn't see the flaw in this argument. But perhaps it isn't so surprising, for such ideas were then fashionable, at any rate in literary circles. The writings of the most recent exponent of this form of vitalism, Teilhard de Chardin, were still influential, and it was still quite natural to picture evolution as inevitably leading from simple single-celled life to the incredible complexity of the human brain.
Although mainstream science has now decisively moved away from the idea of goal-directed evolution, the notion that intelligence is likely sooner or later to appear in any evolutionary system is still prevalent. For example, it is an essential presupposition for the ongoing search of extraterrestrial civilizations. But it presents serious difficulties.
Are there minds beyond the Earth?The computer that sits on my desk is never switched off. It goes on working for twenty-four hours a day, and is awake even when I'm asleep. What it's working on, fulltime or part-time, is the Setiathome program, which is searching for evidence of extra-terrestrial life. I actually think it's highly unlikely that any such evidence will be found, but you never know, which is why I participate in the scheme. Life is probably widespread in our galaxy, but I doubt whether it has produced any intelligence or technological civilizations.
The Barrow/Tipler theoryIn their book The Anthropic Cosmological Principle, John Barrow and Frank Tipler provide an excellent summary of the reasons why the development of intelligence on this planet was probably a unique event. They cite a number of leading evolutionists (T.Dobzhansky, G.G.Simpson, J.Francois, F.J.Ayala, and E.Mayr) who agree with this view, and say that, among evolutionists of note, only S.J.Gould partially dissents. (As we'll see in a moment, Gould really agrees with the others.) Some of their reasons for this view are as follows.
Is intelligence an evolutionary advantage?It often seems to be assumed that the acquisition of a sophisticated nervous system is highly advantageous and has therefore been favoured by natural selection. But this doesn't accord with the facts. Acquiring eyes is certainly an advantage, and eyes have evolved in about 40 different ways. Highly complex nervous systems, in contrast, are very rare. Apart from ourselves and the anthropoid apes, only the cetaceans (whales and dolphins), cephalopods (squids and octopus), and Proboscidea (elephants) seem to have acquired brains that are unusually large for their size (high degree of encephalization), so there is no general trend in that direction.
Moreover, it's quite costly to have a large brain. It needs a lot of supporting structures if it's to be of any use (eyes, ears, limbs to move about), and it's demanding in terms of energy; the human brain requires about 20 per cent of the energy consumed when the body is resting. A large brain has reproductive disadvantages too: it needs a prolonged childhood for education and it makes childbirth difficult; the human brain at birth is probably as large as it can be if the baby is to be delivered at all. Barrow and Tipler conclude: "In short, there is no indication in the geological record that the evolution of intelligence is at all inevitable; in fact, quite the reverse."
Things might have turned out differently—GouldIn his book Wonderful Life, Stephen Jay Gould reaches a very similar conclusion. He maintains that the way life developed on this planet was just one of a large number of possible scenarios, each of which was equally possible at the outset. He mentions seven points at which things might easily have taken a different course. It's worth listing them:
Each of these stages, he claims, might not have occurred. If the tape of life could be rerun, it might go very differently. And, of course, if any of them had gone differently, we wouldn't be here now. Not everyone agrees with this view. Professor Simon Conway Morris, for example, thinks that if the tape were rerun it is very likely that some form of intelligent life would emerge, although not necessarily an intelligent ape. (For an interesting debate between Gould and Simon Conway Morris, see the Unofficial Stephen J Gould Archive. See also my review of Conway Morris's new book Life's Solution.)
As an admitted non-expert, I tend to side with Gould on this. The fraction of evolutionary time for which intelligent life has existed on earth is tiny. It is easy to imagine a world still populated by dinosaurs. If the bolide theory is correct, the only reason it isn't like that now is because of the impact of a meteor or a comet 65 million years ago. But unless you wish to picture God hurling a thunderbolt at the Earth and calling out: "Time's up for you, Dinosaurs; make way for the mammals", this was a purely chance event, which might perfectly well not have occurred. (It's entirely possible, as we are now being told, that something similar will happen again in the near future, resulting in the extinction of intelligent life, at least on this planet.)
The triumph of Homo sapiens?The last act in the drama, so far as we are concerned, is our own origin. Here, too, serendipity rules. Although it is still disputed, the 'Out of Africa' hypothesis has it that modern humans arose very recently, only about 200,000 years ago, from a very small population, perhaps only a couple of hundred strong. If those few ancestors had been wiped out, say by illness, an earthquake, or a volcanic eruption, there would be no technological civilization today.
It would be possible to take the argument down to even finer scales. Was the discovery of agriculture inevitable, for instance? The Industrial Revolution? But we must stop somewhere. For me, the point is made. In Gould's words: "[b]iology's most profound insight into human nature, status, and potential lies in the simple phrase, the embodiment of contingency: Homo sapiens is an entity, not a tendency." (p.320).
Notice, by the way, that the idea of intelligent life as being highly improbable is not just speculation; it's testable. If we succeed in discovering large numbers of technological civilizations in the universe we shall have disproved it; it will follow that there is indeed an inevitable trend towards intelligence. If we fail to find them, on the other hand, this will not prove that alien civilizations don't exist; it will be open to critics to say that they are there but for one reason or another they aren't communicating. However, this view would become increasingly implausible as time went by and nothing was found.
Do we over-value consciousness?If, as seems quite possible, mind is very rare in the universe or even unique to this planet, this suggests what may seem a rather shocking conclusion even to rationalists: do we, perhaps, over-estimate the importance of mind? It's this idea that I want to consider now.
There is no doubt of the importance, to us, of consciousness and subjective experience. These are what distinguish us from the rest of life on this planet. Language, art, philosophy—and science—are supremely significant for us. Indeed, they are all the more important for possibly being unique in the galaxy or even the universe. But this doesn't mean that the universe exists in order to produce minds. The belief that it does may be the last manifestation of anthropocentricism, the ultimate hubristic delusion. (Do bats and birds believe that the purpose of the universe is to produce wings?)
Some people find such ideas shocking or depressing. I don't. The universe is indescribably, unimaginably, rich and diverse, and it is also indifferent to us, our joys, and our sorrows. If we finally destroy intelligent life on this planet it may exist nowhere else at all. Would that necessarily be a tragedy? From our point of view, undoubtedly yes, but the universe would survive. Innumerable species have strutted their hour on the stage of this planet; they've come and gone and will never be seen again. Each of them had its own uniqueness. Conceivably we are just one more member of the crowd; a remarkable one, no doubt, but supremely important and valuable in our own eyes only.
Shakespeare, as so often, got it right:
These our actors,
References and books consulted
Useful websites for material and links about mind: