Does the fact that damaged brains lead to damaged minds mean we can confidently infer that the brain produces the mind? If so, there cannot be an afterlife, at least not in the sense of the survival of a soul. In my experience, people invariably cite this as being their main reason for rejecting an afterlife. Indeed, it often seems to me that the argument against an afterlife virtually exclusively rests on this fact.
I have addressed this issue before, most notably in my Brains affecting Minds do not rule out an Afterlife and The self or soul as a mental substance posts. But I felt it might be useful to have my thoughts on this issue more readily accessible.
I watched the following video entitled Sam Harris: Game, Set and Match.
As a preliminary, I should mention that this video was uploaded to youtube in March 2011. Since then, the person speaking in the video, Sam Harris, doesn't seem quite so certain as he was back then in rejecting an afterlife. However, amongst those who reject an afterlife, the view he expresses here is an extremely common one.
I'd like to draw attention to what Sam says from 1 min 25 seconds. He says:
What we’re being asked to consider is that you damage one part of the brain, and something about the mind and subjectivity is lost, you damage another and yet more is lost, [but] you damage the whole thing at death, we can rise off the brain with all our faculties intact, recognizing grandma and speaking English!
There's applause and some amusement after he finishes speaking those words. And, indeed, I think at first blush this type of argument does seem extremely convincing. So, is it Game, Set and Match to those who deny an afterlife?
Imagine a hypothetical situation where we were all born wearing glasses, contact lenses or something similar, and we could never take them off, at least not during this life. We can imagine someone advancing the following argument about the possibility of the existence of unaided vision:
What we're being asked to consider is that if you damage the lenses in your glasses in one way so as to result in a deterioration of your vision, you damage them in another way resulting in yet further deterioration of one's vision, but yet if the glasses suddenly disintegrated our vision would be fully restored?? You silly people!
Since, in this scenario, no one has ever experienced unaided vision, it seems to me that many people in that hypothetical world would find this as being equally persuasive. Yet we can understand here that the glasses are perfectly capable of affecting our vision without actually creating it. Further, the notion that the glasses could actually produce our vision is deeply implausible since there is no conceivable mechanism whereby this could be achieved. Yes, the lenses in the glasses affect the direction of light entering them and affect our vision, but it would be effectively miraculous to suppose the glasses actually create vision. Even more silly would be the suggestion that the glasses, or at least the lenses within them, just are our vision.
Similarly, it seems to me there is no conceivable mechanism within the brain that could produce consciousness. We have chains of material causes and effects occurring in the brain. These causal chains, like all material causal chains, are exclusively characterised by properties such as mass, charge, momentum, spin and so forth. But, at the end of such chains, something very peculiar is supposed to be created. Rather than anything like the previous material effects, we instead get subjective experiences such as the greenness of grass, the warmth of love, the smell of roses and so on. To my mind, this possibility that brains produce consciousness is, on the face of it, just as outlandish as to suppose our glasses are creating vision. Nor should the complexity of the brain influence our conclusion here. We can assemble Lego bricks to create very elaborate structures, but those structures are never more than the sum of all the bricks. They couldn't produce something wholly different, they couldn't, that is, produce consciousness. Why are so many of us fooled into thinking the brain is any different?
The other alternative is that brain processes, or the causal role they play, just are consciousness. But, to my mind, this is just as silly .. nay.. just as nonsensical, as saying glasses, or the lenses within them, just are vision. I'm sure we can all recognise the latter statement for the nonsense it is, and quite frankly I am perplexed as to why the claim that brain states literally are conscious states is taken seriously for even one second.
I do not dismiss the possibility that brains by some unknown means are producing consciousness. But the fact that the brain can have deleterious effects on the mind, or even apparently eliminate certain aspects of the mind, does not in itself prove this, nor arguably even give very good evidence*. At the minimum, we need more nuanced arguments. Such arguments are seldom given.
So, game, set and match to those who deny an afterlife? Definitely not.
*A lot here rides on how we conceive of personal identity, see my The self or soul as a mental substance. Also, can we meaningfully be said to have evidence in the absence of any conceivable mechanism? Arguably not scientific evidence. See my What do people mean when they say there's no evidence?