Ray Tallis argues that there is no evolutionary explanation of consciousness
We have grown accustomed – perhaps too accustomed – to the idea that every characteristic of living creatures has been generated by the operation of natural selection on spontaneous variation; that it is there because it has, or at the very least once had, survival value or was a consequence of other things that had a survival value. Consciousness, even human consciousness, we are told, is no exception to this rule. Biology does not tolerate anything biologically useless and, given that my brain consumes 20% of my energy supply, and quite a lot of this seems to be used by neurones that are supposed to be responsible for keeping me conscious, consciousness must have a use. And it follow from this that all the things that consciousness enables us to get up to – not only fleeing predators whom we are aware of but also creating art or writing books like The Origin of Species – must also be directly or indirectly related to survival – now, or at some time in the past. Whether or not this is true, the ubiquity of “neuro-evolutionary” accounts of everyday human life is a testimony to belief in the power of evolution to explain consciousness.
But how well-founded is this belief? Was it really natural selection that eventually brought into being creatures that could see that they were naturally selected? Was it the blind laws of physics that so organised the matter in us that it could see the laws of physics and that they were blind? If we are going to address these questions properly, we need to start far enough back to see them clearly. We need to ask by what means consciousness could have come into being – if it was not there in the beginning – and what advantages it confers.
The zero point of evolution is a primitive self-replicator, perhaps a silicate, hardly differentiated, though exquisitely structured, like a crystal. A succession of steps over huge stretches of time, and unconsciously guided by natural selection, led to single cell organisms with their nuclei, organelles, membranes and, eventually, one or two bits of kit such as flagella to aid swimming. That was the story of life for 2.5 billion years until the Cambrian explosion 500 million years ago. Then multi-cellular forms arrived; after which came more complex organisms, with distinctive organs and systems, to deal with the business of keeping the organism stable, accessing nutrients, evading predators, and – when sexual reproduction came on the scene to give natural selection more genetic variation to get its teeth into – finding mates.
The confidence that these developments can be explained in Darwinian terms seems increasingly well-founded; so let us set aside the Creationist appeal to “irreducible complexity”, as evidence that higher organisms could not have evolved step-by-step, and the related claim that Intelligent Design is required to explain the emergence of exquisite structures such as the eye. But what of the other great story: the emergence of sentience, and of more complex consciousness, and ultimately of self-consciousness? How well does this fit into the Darwinian picture?
Very badly, notwithstanding Richard Dawkins’ claim that “Cumulative selection, once it has begun, seems…powerful enough to make the evolution of intelligence probable, if not inevitable” (The Blind Watchmaker p.146). Consider vision: let us begin with the notional “ur-eye”, the light-sensitive spot on the skin of some ancestral creature. This might confer a tiny survival advantage, perhaps making it easier to avoid predators. And one could see how an ever more complex sensitive surface, wiring the organism into ever more exquisitely discriminated and versatile behaviour, might be explained by natural selection. There are now very good accounts of gradual changes, each conferring an advantage, leading to the emergence of the orbit, the retina, the lens and so on, without appealing to Intelligent Design. And there are plenty of intermediate forms, demonstrating the benefits of having photosensitive structures marking the staging posts to the kind of complex eyes seen in higher organisms. But this story doesn’t address three problems that a satisfactory evolutionary account of consciousness would need to deal with. Consider the emergence of sight from photosensitivity.
Firstly, chemical or electrochemical sensitivity to light is not the same as awareness of light. Secondly, the content of awareness of light – brightness, colour, never mind beauty or meaning – is not to be found in electromagnetic radiation, which is not intrinsically bright, coloured, beautiful or meaningful. These secondary and tertiary qualities are not properties of the physical world and the energy in question. Thirdly, it is not clear how certain organisations of matter manage to be aware – of impingements of energy, and later of objects, and (in the case of humans) of themselves – when very similar organisations of matter do not have this property. This problem is more evident much further down the evolutionary path, when we look at neurones that are, and those that are not, associated with consciousness in the human brain and see how little distinguishes them. The biological story of the evolution of the eye from single cells to full-blown eyes tells us nothing about the journey from light incident on photosensitive cells, producing a programmed response, to the gaze that looks out and sees, and peers at, and inquires into, a visible world.
There is no reason to assume that photosensitivity brings awareness of light, however cunningly the relevant structure is wired into discriminative behaviour that will promote survival. Computers, after all, do not get any nearer to being conscious as the inputs are more complexly related to their outputs, however many stages and layers of processing intervene between the two. There is nothing, in short, that will explain why matter in a certain form will go “mental”. Or not unless we anticipate and borrow, on account as it were, the notion of an organism that is aware of its environment. We have to be on our guard: this anticipatory borrowing may be implicit even in the conceptual distinction between organism and environment; it slips the notion of viewpoint into a starter pack that consists only of matter. Indeed, the contrast between environment and organism already contains an embryonic hint of the differentiation between a subject and its objects; howsoever this might be concealed by treating organisms as physical systems. Without this fudge, it is difficult to see how energy exchanges between parts of a physical system would count as “inputs” and “outputs”. The fudge conceptually smoothes out the steps towards consciousness and makes the extraordinary claim that when matter assumes certain configurations it acquires mentality seem less extraordinary.
This forestalls our asking this entirely valid question: Even if consciousness conferred advantage, how it could become available to genes via the organisms that are the vehicles ensuring their replication? This question arises whether we are considering a single photosensitive cell, or a human eye, or the human being aware of other human beings in a shared world built up out of pooled experience. The explanatory gap – the jump from energy exchanges to awareness – just happens to be more evident in the case of single energy-senstive cells, which lie at the putative beginning of consciousness, though it is concealed by the assumption that the single cell has only a “teeny weenie” bit of consciousness that can be smuggled into the material world without its laws being bent or broken. But the question remains: How is it that certain configurations of matter should be aware, should suffer, enjoy, fear etc? What is there in matter, such that eventually certain configurations of it (human beings) pool that experience and live in a public world? No answer is forthcoming, which is why many materialistically inclined philosophers like to deny the real existence of consciousness, in particular those basic elements of subjective experience, so-called “qualia”.
Even if we were able to explain how matter in organisms manages to go mental, it is not at all clear what advantage that would confer. Why should consciousness of the material world around their vehicles (the organisms) make certain (material) replicators better able to replicate? Given that, as we noted, qualia do not correspond to anything in the physical world, this seems problematic. There may be ways round this awkward fact but not round the even more awkward fact that, long before self-awareness, memory, foresight, powers of conscious deliberation emerge to give an advantage over those creatures that lack those things, there is a more promising alternative to consciousness at every step of the way: more efficient unconscious mechanisms, which seem equally or more likely to be thrown up by spontaneous variation. Think, after all, what unconscious mechanisms can achieve: the evolution of most of the universe; the processes that are supposed to have created life and conscious organisms; the growth, development and most of the running of even highly conscious organisms such as ourselves. If you had to undertake something really difficult – for example growing in utero a brain with all its connexions in place – consciousness is the last thing you would want to oversee the task. OK, successful intra-uterine development relies, in the case of higher organisms, on a conscious mother choosing the right mate and getting the right food and so on. But that is to put the cart before the horse. Once you have a species that depends on consciousness, then it is essential for its members to remain conscious. But if we assume the materialist viewpoint and, unlike many evolutionary biologists, adhere to it consistently, and set aside an anthropocentric viewpoint that sees the entire evolutionary process as something that was always leading up to us or creatures like us, it seems highly implausible that, in an unconscious biosphere, consciousness, even if it were on offer, would seem like a good option.
Those who think consciousness confers advantage tend also to believe that it confers even more advantage as it gets more complex. They argue that complex consciousness permits planning, deliberation, the rehearsal of possible courses of action before commitment to one particular course (putting scenarios rather than flesh on the line), and (as David Hodgson brilliantly argued in The Mind Matters) to enable organisms to engage with wholes, with singular combinations that cannot be captured by general laws. Leaving aside the fact that “parts” and “wholes” count as such only in the context of a consciousness that puts them together or pulls them apart, this illustrates a deeper problem, common to many evolutionary apologists for consciousness: that of approaching its origin from the wrong direction – through the lens of existing life, indeed existing conscious life. Looking prospectively from the beginning rather than retrospectively, one could argue that an organism that has to plan, to deliberate, to rehearse possible courses of action, and has to see wholes so as to deal with singulars, in order to survive, is in a mess. Of course, once in the mess, it would be better off with better consciousness – and this applies irrespective of whether we are considering threats and opportunities from the material environment, other species, or competition from conspecifics. Yes, my genes would have a better chance of replicating if I had better memory or more foresight than you. But we need to start further back and ask by what disastrous processes did conscious, especially complex conscious, species get into this situation – where there are errors to be avoided or corrected? After all, mechanisms do not make mistakes: they are simply the expression of the unbreakable laws of physics. A deliberating creature that has increased capacity to get things right does so only because it has a propensity to get things wrong. A fully adapted organism would not have to deliberate.
And what is deliberation, planning, anyway? Do organisms really operate on the laws of physics as if from the outside? And if they do not, as the materialist view of life requires us to believe, then there is no way that planning and deliberation – or the illusion of planning or deliberation – could serve a function. No wonder many evolutionary biologists and neuroscientists often deny that free will is possible and marginalise the role of consciousness in human life. How, within the materialist world picture, is consciousness able to inflect the laws of physics to make the world a more hospitable place for the organism that is conscious? From the standpoint of a consistent materialism, no organism that was going to make the cut would have deliberately to work with the laws of physics, never mind work against them or trick them into doing its will.
And there is a serious difficulty with the notion of “better and better” consciousness that will compensate for the disadvantage of having to work through consciousness in the first place. We have seen how consciousness is profoundly dissociated from the material world in which organisms are generated and their fate decided; so it is difficult to see how the content of consciousness could get closer to the relevant truths of that material world which for materialists is all that there is. For some writers, such as Paul Churchland (see Matter and Consciousness), the criterion for intelligence – that catch-all term for premier cru consciousness – is that the organism is more closely coupled into its environment. If that were true, then a silicate crystal, so hard-wired into its environment that no wires are required, would be just the thing to be. Of course, intelligence makes us loosely rather than tightly wired – hence the possibility of deliberation between possible courses of action.
If it is difficult (though not impossible) to see how life emerged out of the operation of the laws of physics on lifeless matter, it is even less clear how consciousness emerged or why it should be of benefit to those creatures that have it – or more precisely, why evolution should have thrown up species with a disabling requirement to be conscious and to do things deliberately and make judgements. Why would life evolve towards such losers who have to get things right in order to do the right thing by themselves? We humans have of course benefited enormously from being conscious: we dominate the planet. But it is only very recently that our consciousness, and its pooling in an extraordinary shared human world, has significantly increased our traction on the laws that are supposed to have brought us into being – and made up for the disabling burden of consciousness and the requirement to be more conscious to get ahead of the game, including most intimate competition between replicators – between members of the same species.
Consciousness makes evolutionary sense only if one does not start far enough back; if, that is to say, one fails to assume a consistent and sincere materialist position, beginning with a world without consciousness, and then considers whether there could be putative biological drivers for organisms to become conscious. This is the only valid starting point for those who look to evolution to explain consciousness, given that the history of matter has overwhelmingly been without conscious life, indeed without history. Once the viewpoint of consistent materialism is assumed, it ceases to be self-evident that it is a good thing to experience what is there, that it will make an organism better able so to position itself in the causal net as to increase the probability of replication of its genomic material. On the contrary, even setting aside the confusional states it is prone to, and the sleep it requires, consciousness seems like the worst possible evolutionary move.
If there isn’t an evolutionary explanation of consciousness, then the world is more interesting than biologists would allow. And it gets even more interesting if we unbundle different modes of consciousness. There are clearly separate problems in trying to explain on the one hand the transition to sentience and on the other the transition from sentience to the propositional awareness of human beings that underpins the public sphere in which they live and have their being, where they consciously utilise the laws of nature, transform their environment into an artefactscape, appeal to norms in a collective that is sustained by deliberate intentions rather than being a lattice of dovetailing automaticities, and write books such as The Origin of Species. Those who are currently advocating evolutionary or neuro-evolutionary explanations of the most complex manifestations of consciousness in human life, preaching neuro-evolutionary aesthetics, law, ethics, economics, history, theology etc, should consider whether the failure to explain any form of consciousness, never mind human consciousness, in evolutionary terms, might not pull the rug from under their fashionable feet.
Raymond Tallis is emeritus professor of geriatric medicine at the University of Manchester, a philosopher, poet, novelist and cultural critic. His many books include The Enduring Significance of Parmenides: Unthinkable Thought (Continuum) and The Kingdom of Infinite Space (Atlantic).