This post was adapted from a talk by Dr. Alan Lightman called Fact and Faith: A Meditation on Science and Religion, organized and moderated by Sinai and Synapses Fellow Adam Reynolds as part of the MIT Addir Fellows Interfaith Dialogue, a yearlong program where MIT students (graduate and undergraduate) meet weekly for interfaith dialogue. You can listen to the full lecture, with Q&A, above.

For thousands of years, we human beings have been torn between the material and the immaterial. Modern science has shown that all things in the material world are impermanent and ultimately pass away. We thought atoms, which were once thought to be indivisible and and indestructible, can be split, and we know even that their pieces can be split. And we don’t know how long or how far that splitting continues. Stars which are once thought to be eternal, and even the symbols of the Divine, are now known just to be material, and they eventually burn up their nuclear fuel and pass away. And even our entire universe, which was once thought to be the ultimate unity, now a number of leading physicists hypothesize that our universe is just one of many universes called the multiverse, many of which would not have conditions that allow life at all.

So modern science has, one by one, shown that everything in the material world is temporary and passes away. And yet, we long for something that is eternal. Part of us wants to reduce everything to atoms and molecules, which are governed by logic and laws and suffer the impermanence of all material things, and part of us wants to resist that temptation and believe that some things defy that kind of reduction. This tension between the two desires has been the source of our science on one hand and our art and religion on the other. This tension comes into the discussion of free will vs. determinism, of ethics and morality, of art and aesthetics. It’s related to the definition and boundaries of science and what constitutes faith. So it was this tension that excited me and propelled me to write my book Searching for Stars on an Island in Maine, and actually it’s been a tension I’ve been interested in for many years.

My book attempts to explore some of these tensions and questions. It draws from recent discoveries in science, but also draws from the thinking of theologians and philosophers and writers, from St. Augustine to Aristotle to Emily Dickinson. But these are weighty, heavy issues, and one thing you learn as a writer at some point is you don’t confront a weighty issue head on, you sort of do it tangentially. So I’ve written the book as an extended meditation, thinking about these things as I wander about the island in Maine, in the same way that Walden, Henry David Thoreau’s great book, feels like a meditation and Annie Dillard’s wonderful book Pilgrim at Tinker Creek feels like an extended meditation as she wanders about Tinker Creek. So that’s sort of the feeling in the tone of the book, and also the way that I’ve tried to address these questions myself.

I want to discuss some of these issues in a more personal way. I would argue that most of our religious and spiritual beliefs are motivated by knowledge of our own mortality. We confront our physical demise by invoking the eternal, the immortal soul, God, and so on. All material things are made of atoms and molecules, and those are parts of the physical world. And according to the view of science, all material is governed by laws. As I’ve said, immortality is not allowed by the laws, disembodied existence is not allowed by the laws, and insubstantiality is not allowed by the laws. And as I told you earlier, I am a materialist, but I also consider myself a spiritual person. So I am what you might call a spiritual materialist.

So how does such a person, a spiritual materialist, confront his own impending death? For this particular materialist, I believe that the distinction between life and death is overrated. And I’ve come to believe the death occurs gradually through the diminishing of consciousness. So let me explain. According to the scientific view, we’re all made of material atoms and nothing but material atoms. And to be precise, the average human being consists of several thousand trillion trillion atoms. 65% oxygen, 18% carbon, 10% hydrogen, 3% nitrogen, and so on. And the totality of our tissues and organs is made of these atoms. And according to the scientific view, there’s nothing else.

So to a vast cosmic being looking at human beings, each of us would be this special assemblage of atoms, humming along with this various chemical and electric activities. Of course, it is special – a human being is different from a rock. But we’re a collection of atoms, and the mental sensations that we experience as consciousness and thought, according to science, are purely material consequences of the purely material electrical and chemical signals exchanged through and between neurons – which are material. And they themselves are composed of material atoms and molecules. And when we die, this special assemblage of atoms that is a human being disassembles. The atoms remain, only scattered about.

Particularly special in these considerations is the brain. In the view of science, the brain is where our self-awareness originates, our memories are stored, our sense of self, our sense of ego. Of course, neurologists have studied the brain in great detail. We know a lot about the brain; there’s a lot that we still don’t know, but the materiality of the brain is not in doubt. There are about 100 billion neurons in the average human brain, and each neuron is connected by filaments to 1,000-10,000 other neurons. And the electrical and chemical components of the neurons are largely understood. The creation of long-term memory, the growth of new connections, of synapses, the strengthening of those synapses, much of that is understood.

But despite the known materiality of the brain and the knowledge of how a lot of these processes occur, the sense of ego, the sense of I-ness, the sense of consciousness, is so powerful and compelling and difficult to describe, that we endow ourselves and other human beings with some mystical quality, some magnificent and non-material essence that blooms much larger than just a collection of atoms and molecules. To some people, that mystical thing is the soul, to some it’s the self, and others it’s consciousness. The soul, as commonly understood, we cannot discuss scientifically, so I’m going to leave that alone, but that’s not true with consciousness. Isn’t the experience of consciousness an illusion caused by the trillions of neuronal connections and electrical and chemical flows between them? And if you don’t like the word illusion, then stick with the sensation itself. You can say that “consciousness” and “self” is a name we give to the mental sensation of all of those electrical and chemical exchanges and signals in the material brain.

And I don’t mean to diminish the grandeur of the material brain. I mean, our brain is capable of art and science and music and everything we’re able to do, but I do claim here that it’s all atoms and molecules. And if our giant cosmic being examined a human being in detail, they would see fluids flowing, sodium and potassium gates opening and closing, electricity flowing along neurons, acetylcholine in synapses, but he/she/it, this cosmic being, would not find a self. The self and consciousness, I think, are names we give to those sensations.

If someone began dissembling my brain one neuron at a time, depending on where the process began, I might first lose a few motor skills, then I might lose a few memories, I might lose a sense of where I am, the ability to recognize faces. And during the slow taking apart of my brain, one neuron at a time, I would become more and more disoriented. Everything that I associate with my ego and my consciousness would gradually dissolve into a bog of confusion. And the doctors in their blue and gray scrub suits who were taking apart my brain one neuron at a time, they could drop each neuron into a metal bowl. You wouldn’t hear it because the neurons are very soft. And slowly, I would lose everything that we associate with consciousness.

And of course, people who are suffering from dementia actually go through this. If we conceive of death as nothingness, we can’t imagine it, but if we conceive of death as the complete loss of consciousness, which is a view supported by the understanding of the body as an arrangement of material atoms, then we can approach death in gradual stages as consciousness fades and dissolves. And the distinction between life and death would no longer be an all-or-nothing proposition. And this is what I mean when I say I think the distinction is overrated. And as I said, you probably know people who are suffering from dementia. It’s a very grim process. I have a friend who’s suffering from aggressive Alzheimer’s. She writes me every month, and I can see that she’s slowly losing her mind.

Now, I wanted to end with something truly personal, and here I will show my personal conflict between them the material and the spiritual. From a scientific point of view, I believe completely everything that I’ve just told you about consciousness, the ego, the brain, atoms, molecules – but I’m not satisfied with that picture. In my mind, I can still see my mother dancing the bossa nova, and I can still hear my father telling his “Cooshmaker” joke, even though they’re long gone. And I wonder where are they now, my mother and father. I know the materialist explanation that I’ve just said, but that doesn’t do anything to relieve my longing for them, and the impossibility that there are no longer here.

I have a confession to make: I’m enjoying the illusion of consciousness. I’m enjoying the illusion of life. Even though I believe that I’m only a collection of atoms that my awareness is passing away neuron by neuron, I’m content with this illusion. And even though I don’t believe in a Heaven or Hell, and I don’t believe in an immortal soul, I take some pleasure in knowing that 100 years from now, and even 1,000 years from now, that my atoms will still be here – my individual atoms. The atoms will not know where they came from, but they will have been mine. Some of them will have been part of the memory of my mother. Some of them will be part of the memory of the vinegary smell of the first apartment that I lived in. Some of the will be part of this hand right here. Those atoms will still be here 1,000 years from now.

And if I could label each of my atoms at this moment with my social security number and track each one for the next 1,000 years after this particular assemblage of atoms became unassembled, some of those atoms would dissolve in the ocean, some of them would go into the ground and be absorbed by plants, some of them would float in the air, some will become parts of other people 1,000 years from now. Particular people. If you followed the atom with my Social Security number, it would land up in particular people 1,000 years from now. Some will become parts of other lives and other memories. And some, after that long long journey, will return to the island in Maine.