1. The arguments for the thesis that the brain produces consciousness
To believe in an afterlife, at least in the form of a soul dwelling in some afterlife realm, is to suppose our consciousness can exist independently of our bodies. However, there appears to be a crippling obstacle to holding such a view, namely the apparent dependence of our mental states on a properly functioning brain. For example, our capacity to understand written and spoken words and the capacity to speak are impaired or even eliminated with injuries to certain regions of the brain. Damage to the hippocampal and thalamic areas of the brain can destroy one's ability to store new long-term memories. More radically, injury to the brain can result in significant personality change; the most famous example here being undoubtedly Phineas Gage. To top it all off, we could also point to the fact that drugs have a propensity to affect our emotions, attitudes, and dispositions. Indeed, even alcohol and caffeine do this. Taking all this into account, it seems more or less certain to many people that it is the brain that somehow or other gives rise to our consciousness – that is it is the brain that gives rise to all our thoughts, feelings, perceptions and so on. Hence, how could our consciousness possibly survive the death of our bodies and brains?
In my experience, proponents of an afterlife appear to largely ignore these facts. Instead, they counter with the evidence for an afterlife such as NDE’s, mediumship, recollections of alleged previous lives, and so on. The problem here is that if it is indeed the case that the mind-brain correlations makes it more or less certain that the brain produces consciousness, then such evidence, no matter how apparently powerful, cannot possibly point to an afterlife. Hence, for example, NDE’s, interesting as they may be, cannot possibly represent any sort of encounter with some afterlife realm. They must somehow be hallucinations produced by the brain.
2. Reasons to question this thesis
Let’s consider the following argument:
It surely must be obvious to everyone that eyeglasses actually create vision. Changing the lenses affects the vision in certain characteristic ways. One can make one's vision worse, or better. One can make one be able to see in the distance, but not close up; or conversely, to see close up, but not at a distance. We can invert peoples' vision. We can make people see everything in blue, or red, or green; you name it. Or all blurry. By painting the lenses black we can even eliminate one's vision completely! And all these effects are consistent across different people.
Of course, we know that eyeglasses don’t create vision. Indeed, we know in principle that eyeglasses could not create vision all by themselves since there is no appropriate mechanism, or conceivable causal chain, whereby vision could be created. Extra ingredients are required; namely eyes and the part of the brain dealing with vision.
Other examples apart from eyeglasses can be considered. Thus, consider a prism. The mixture of coloured lights obtained is not wholly produced by the prism all by itself. Something extra is involved, in this case, the white light that enters the prism. Or consider a TV set. The internal components all by themselves do not produce the programmes. Similar to the prism something else is involved, in this case, TV signals.
How can we be so confident that the relationship between our consciousness and our brains (and more generally our bodies) is not of a similar nature to these examples? Perhaps our conscious states are merely affected by our brains? Perhaps the brain merely either facilitates or inhibits the ability to perceive, think, feel, deliberate and so on, not creates them? Is this plausible?
The unreflective view is that consciousness is supposed to come into being as the end consequence of material chains of causes and effects. Such causes and effects are cashed out completely in the form of processes that we can measure; namely particles with physical properties such as charge, momentum, spin and so on. Each link in the chain of causality follows as a direct result of these properties. But, at the end of such causal chains, we get a sudden abrupt change, a radical disconnect from these measurable processes to subjective experiences such as the greenness of grass, the warmth of love, the smell of roses and so on. These subjective experiences do not have physical properties, so we cannot, seemingly in principle, derive them from the prior physical causal chains.
So, if consciousness is indeed produced by the brain, then it seems it just suddenly springs into existence. I am not able to understand how this differs in any substantive manner from supposing eyeglasses could actually create vision rather than merely modifying it, or prisms actually produce colored light rather than merely modifying existing white light, or the innards of TV sets actually create the programs shown rather than merely modifying and changing TV signals. Of course, in these other examples, we know how the end phenomenon comes about. Yet, if we lacked this knowledge, we surely would not, for example, suppose that the innards of a TV set, all by themselves, could produce TV programs with their storylines. It would be miraculous. Why should the supposition that the brain creates consciousness be considered to be different, to be any less miraculous? Why reject the more plausible alternative that consciousness exists all along, with the brain merely serving to facilitate or inhibit conscious states?
3. The Materialist Option
People are aware of this problem of how the brain creates consciousness, or at least philosophers are. By far the most common solution, at least amongst the scholarly community, is to adopt a position called materialism. Modern materialism is essentially the position that science, or at least some ideal science, investigates the totality of reality. Since science investigates reality via its measurable aspects, modern materialism holds that only these measurable aspects of reality exist.
In section 2 I mentioned that subjective experiences are supposed to come into being as the end consequence of material chains of causes and effects. Materialism denies this. Since modern materialism holds that only these material chains exist, there can be no additional facts in the form of subjective conscious experiences that we cannot measure. Instead, conscious experiences are typically either conflated with appropriate material processes within the brain, or conflated with the causal role that such material processes play.
It’s hard to get across how radical materialism is. It is far more than simply saying the brain somehow produces consciousness. Rather, strict modern materialism asserts there is only the brain and processes within it, and consciousness -- at least in terms of qualitative subjective experiences -- is somehow illusionary, that it has no real concrete existence at all. I do not regard such a position as tenable and I go into detail why I believe this here and here. However, even if one were to argue that it is tenable, why on earth believe it? I have argued that although consciousness is affected by the brain, it is not necessarily produced by it. In fact, it seems the only way it could be produced by the brain were if some variety of materialism is correct. But we were never forced into supposing the brain must produce consciousness in the first place. Hence, even if -- contrary to my own position -- it were possible to argue modern materialism is a viable position, there is no need to adopt such an uncommonsensical position.
4. An Objection
This being so, if there’s an afterlife, what survives? Myself as a child at 7 years of age, or as a young adult at 21, or when I’m an old man at 81? Or some other age? When drunk or sober? Does the impossibility of answering this question suggest that the brain must somehow produce consciousness?
This issue pertains to personal identity. What is it that makes me the very same person from one decade to the next, or indeed one day to the next? If we cash out personal identity in terms of intelligence, interests, memories and so on, it seems we do not literally survive from childhood to adulthood. This entails that not only is there no afterlife, but given that I’m now an adult, my 10 year old self has now quite literally ceased to exist. And when we imbibe lots of alcohol our sober selves quite literally cease to exist, even if only temporarily.
But why subscribe to such a radical uncommonsensical notion of personal identity? Perhaps what constitutes the self is not my interests, intelligence, memories and so on. Perhaps what constitutes my self is that sense of me-ness that has endured since I was a child, to when I'm drunk, to what I am now. Consider a table. Depending on what it is made of, it might acquire certain types of scratches as it grows older. But, no matter how many scratches it acquires, it is still the very same table. The scratches do not comprise the table, even though what the table is made of determines the type of scratches and how easily it acquires them. In a comparative manner, maybe my interests, intelligence, memories and so on do not comprise my self even though my self influences them. Going back to the eyeglasses, my vision can be altered in a variety of ways by trying on differing eyeglasses. Nevertheless, that does not alter the fact that there is an unaided vision which remains unchanged throughout my life, even though we may never experience it. It might be the case likewise for my self, and it is this self that survives should there be an afterlife.
It seems to me that the mind-brain correlations argument against an afterlife is significantly less compelling than people think. If the afterlife hypothesis is to be regarded as an extraordinary one, then it is my position that other arguments or evidence, apart from the mind-body correlations, need to be appealed to. However, I am not aware of any other such arguments. Of course, even if it is not regarded as an extraordinary hypothesis, it needn’t be true either. Implausible that it might be, perhaps consciousness does suddenly appear with a functioning brain, even though we lack any conceivable causal chain as to how this could happen. Philosophical speculation can only take us so far. We also need to look at the evidence for an afterlife – NDE’s, memories of past lives, mediumship and so on – before reaching any provisional conclusions.
P.S. I attempted to get this essay published in a magazine called Philosophy Now. It was rejected, moreover it was rejected within approximately 5 minutes after I had sent it. I cover what happened here.