Do you believe that your mind, personality, or self is an essence that exists independent of your physical brain? Do you think of you as a spirit or soul, temporarily constrained and residing in the organ that is your brain—an immortal consciousness merely housed in your earthly body?
If so, you are among the majority of all people, and your intuitions about mind-body (or mind-brain) dualism are entirely normal and psychologically adaptive.
Mind-brain dualism is the view that brain and mind are derived from entirely different kinds of things—physical stuff and mind-stuff. Dualism assumes that both kinds of stuff exist in the universe and that science has simply not yet detected and discovered the mind-stuff. Dualism feels intuitively correct to most people, as it fits with our subjective experience. But it is completely contradicted by science.
Scientific evidence versus intuition
Science is often jarringly counterintuitive. Familiar examples are the way that science forces us to accept that we are not living on a flat Earth and that there really isn't any absolute direction of up and down. Just as counterintuitively, science teaches us that space and time are not absolute but instead are relative and curved. And, in the very practical business of trying to determine whether a purported treatment actually causes an outcome that happens to occur after taking the treatment, the scientific method meticulously bypasses and neutralizes our intuitions.
That's why you should have much more confidence in a randomized double-blind placebo-controlled trial of a treatment that has been subjected to expert critical peer review and has been independently replicated, whereas you should be highly skeptical of an alternative therapy that is based on anecdotal evidence and marketed by glowing personal testimonials without robust evidence to back it up.
The scientific view of the mind-body question
So what does science tell us about the mind-body / mind-brain question? While it certainly is true that science is just beginning to figure out how the mind or self emerges from the physical brain, science is nevertheless unequivocal that the mind is the product of the brain and nothing but the brain. There is no aspect of the mind, the personality, or the self that is not completely susceptible to chemical influences or physical diseases that disrupt neuronal circuitry. The mind is (only) what the brain does. This view is called monism (or physicalism or materialism), as opposed to the dualism described above.
Monism (literally: one-ness) holds that there is only one kind of stuff in the universe—physical stuff: matter and energy (which are interchangeable with each other). Monism maintains that mind is an emergent property of matter and energy when matter is organized in particular kinds of complex ways. Moreover, matter achieves this immense complexity through spontaneous unguided processes of self-organization, further sculpted in biological organisms by powerful evolutionary forces (again, unguided). The fact that such ingenious, intricate complexity is possible in an unguided way, without an Intelligent Designer, is another of those counter-intuitive insights provided by science. How exactly it is possible and how it all works is pretty much the subject of the entire field of science.
Rest assured that this is the overwhelming mainstream scientific consensus. Though there is certainly a sizable minority of scientists who do hold personal spiritual beliefs (scientists are inclined toward the same human intuitions as everyone else and have to work hard to consciously over-ride them), those beliefs can only coexist in a psychologically compartmentalized manner in relation to the principles on which those scientists base their professional work. Spiritual / supernatural / paranormal ideas are entirely incompatible with science. There is simply no room for belief in a spiritual realm, in a scientific view of reality. Period.
Might science have simply not yet discovered the ‘mind stuff’ or spiritual realm pervading the universe?
Spiritual believers often accuse scientists of being closed-minded or dogmatic, for being so definite in their rejection of mind-brain dualism and a spiritual realm. So, how is it that scientists are so certain that dualism is false? Quite simply, because for dualism to be true, all of science would have to be false.
But wait a minute, you say. There have been many scientific theories overturned in the past by better theories and new evidence, producing paradigm-shifts. Isn't it possible that dualism will replace monism just as surely as Einstein's Theory of Relativity superseded Newtonian physics? The analogy is misleading. Paradigm shifts do sometimes occur, but overturning the foundations of science is quite another matter, the likelihood of which is astronomically small.
Dualism so fundamentally contradicts the foundations and entire accumulated evidence of modern science that in order for it to be true, we would have to start rebuilding modern science from the ground up. If dualism turned out to be true, it would also be a complete mystery or fluke as to how most of our advanced technologies (including all of our electronics) work at all, since their design and engineering are based on the very principles that would necessarily be entirely invalidated if dualism were true.
If the idea of a spiritual realm and a mind that outlives the brain turned out to be true and materialism turned out to be false, then this discovery would not just add new insights to science the way that the revolutionary theories of relativity and quantum mechanics did, it would contradict science in its entirety. See footnote1 for a cogent explanation by a renowned physicist as to why this is so.
The scientific project to explain how consciousness emerges from matter is now underway
We don't yet know exactly how consciousness emerges, and very many intriguing mysteries remain. We're still at an early stage in the process of the serious scientific investigation of consciousness. But neuroscience has already made enormously impressive inroads into understanding the mind-brain relationship, and we do already have many compelling insights and hypotheses to point us toward an eventual understanding of how the brain produces subjective conscious experience (see for example the posts in footnote 2)
Life after death?
So what happens to the mind, or the self, after death? If there's no basis for dualism, the answer is a no-brainer (no pun intended). The moment the brain loses its exquisitely synchronized organization, consciousness is lost. If that breakdown of physical processes is irreversible, consciousness is permanently extinguished, and the unique organization of matter that constituted that individual's personhood, self or essence ceases to exist.
But since humans are instinctive dualists, the idea of life after death makes complete sense to our intuitions. And that’s not the only reason why the belief comes so naturally to people.
Death has never been popular. Especially when it is seen as the final and utter cessation of being. The prospect's tolerability increases only when it is reframed as a mere passage to a heavenly paradise filled with all manner of delights—all the more so for those who are suffering or disadvantaged in this life. Humans are profoundly egocentric, and it is natural for us to frame the world in self-referential terms. We cannot easily conceive of the world existing without us, and we struggle to imagine our absolute nonexistence. Even those who do contemplate death as a complete cessation of existence in any form tend to imagine how being dead would feel. It's no surprise that belief in life after death is an irresistibly appealing idea that has emerged in diverse forms throughout history. Indeed, the denial of death may be the raison d'être of religions.
Most religions share common beliefs about some sort of eternal essence surviving the decay of our body, which is viewed as a mere vessel or vehicle for the soul. From a very early stage of prehistoric development, it appears that humans have been conscious of and preoccupied with death. Anxiety about death, denial of death, and various forms of belief in an eternal afterlife and the spirits or gods that inhabit and govern such realms have defined practically every religion in human history and prehistory.
For the cynics and pessimists who argue that there’s no point to life if it’s finite
Some ask: What is the point of trying to accomplish anything if there is no larger purpose to the universe? What's the point if we simply cease to exist after we die? As I've written elsewhere:3
Even among those with the gloomiest or most uninspired outlook on life, any otherwise mentally healthy person possessing moderate empathy and humanity and a little ability to transcend egotism and solipsism can be moved to care enough to do something, anything, to mitigate suffering and increase happiness in other people. The suffering and happiness of other people are as real as our own and will continue long after we die. We might doubt whether our own existence matters. But others will continue to exist, and others after them. We all have the opportunity to affect others while we are alive, and how we do so will continue to matter to those others long after we are gone.
As many people know, when you live your life with a commitment to others, a lot of really good things happen to you. Your own life becomes much more satisfying, enriched, and meaningful. There are few ways to feel that your own life matters more than being committed to other people (Or other animals, or even plants, if that's your preferred commitment and if you don't relate well to people). And people will generally reciprocate your caring and devotion.
You only live once. Make it count. This is not a dress rehearsal. Life is short and time moves fast.
How will it actually feel to be dead? Well, remember how you felt for all those eons before you were born? Just like that.4, 5
1. Caltech physicist Sean M. Carroll framed the debate this way, in his book The Big Picture: On the Origins of Life, Meaning, and the Universe Itself (New York: Dutton, 2016): "Is consciousness 'just' a way of talking about the behavior of certain kinds of collections of atoms, obeying the laws of physics? Or is there something definitely new about it—either an entirely new kind of substance, as Rene Descartes would have had it, or at least a separate kind of property over and above the merely material?" (p. 319). Carroll argued persuasively for the former (just atoms obeying the laws of physics). He went on to say "If these mental properties affected the behavior of particles in the same way that physical properties like mass and electric charge do, then they would simply be another kind of physical property. You are free to postulate new properties that affect the behavior of electrons and photons, but you're not simply adding new ideas to the Core Theory; you are saying that it is wrong. If mental properties affect the evolution of quantum fields, there will be ways to measure that effect experimentally, at least in principle—not to mention all the theoretical difficulties with regard to conservation of energy and so on that such a modification would entail. It's reasonable to assign very low credence to such a complete overhaul of the very successful structure of known physics" (p. 356). Carroll explained elsewhere why physicists are extremely confident now that the Core Theory is correct, and he explained what the theory entails. He also (like many other physicists) went on to debunk popular New Age beliefs (e.g. those promoted by Deepak Chopra) that quantum mechanics somehow supports the notion that the universe is pervaded by some sort of primal innate consciousness and the notion that consciousness is primary, creating matter (vs. the scientific view that consciousness is secondary, arising from matter). For a short, simplified version of the above explanation by Carroll, see https://www.wired.com/2016/05/thinking-psychic-powers-helps-us-think-science/.
2. The Physical Evolution of Consciousness; Do You Have Free Will?; How Could Mind Emerge From Mindless Matter?; What Actually Is a Thought? And How Is Information Physical?; Where Does Purpose Come From? (If the Universe Had None).
3. Parts of this article are taken from: Ralph Lewis, Finding Purpose in a Godless World: Why We Care Even If The Universe Doesn’t (Amherst, NY: Prometheus Books, 2018). (This passage also appeared in the blog post Can Life Have Meaning in a Random Universe?) The book is a deeper dive into questions of purpose, meaning and morality in a random, purposeless, godless universe. Among other topics, the book also discusses in more depth the mind-brain problem, the reasons why humans are instinctive dualists, and a deeper biological and psychological understanding of death.
See this YouTube video link for an engaging Power Point presentation in which Dr. Lewis explains how a family health crisis focused him on coming to terms with the outsized role of randomness in life, and to wrestle with the question of whether the scientific worldview of a fundamentally random universe is nihilistic. He summarizes how science has come to view the universe and absolutely everything in it as the product of entirely spontaneous, unguided processes, and why this is actually a highly motivating realization for humankind. Or see this link for a very brief video providing a synopsis of the book.
[CLICK 'MORE' TO VIEW FOOTNOTES 4-5]
4. As for so called Near Death Experiences (NDEs) supposedly providing evidence for an after-life, these have been very thoroughly debunked. For just one of many clear handlings of the subject, see Michael Shermer, Heavens on Earth: The Scientific Search for the Afterlife, Immortality, and Utopia (New York: Henry Holt, 2018).
5. For readers seeking a scientific understanding of the nature of consciousness, my five-part blog series on the biological evolution of consciousness will be of interest: "What Actually Is Consciousness, and How Did It Evolve?" As stated there, trying to understand and speculate on the nature of consciousness without a fairly deep understanding of biology and neuroscience is a futile undertaking. There is a lot of pseudoscience on the subject of consciousness that lays claim to a scientific basis. One common reason why such fanciful and wishful theories are fundamentally incompatible with real science is that from the outset they lack a detailed and sophisticated understanding of biology and neuroscience.