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If you take an absolutely scientific approach to life, you do not have much to say about death, except that the life process—whatever it might be—stops. And so, when you die, your mind goes blank. You go away. In the imagery of the Buddha, you go out like a candle. You as a person, a process of insight and expectation and memory, cease to exist. All you that have known, hoped and expected, learned and discovered disappears.1
But we don’t know, exactly, what that the life process is. We have begun to track it at the level of the cell: an interplay of chemical energy absorbed in the form of nutrients, prepared as high-energy phosphate bonds in the mitochondria, and expended elsewhere in the cell through the breaking of those bonds. In multi-celled creatures, individual cells also communicate with each other chemically by releasing, bathing in, and reacting to special proteins—hormones, antigens, kinins, and their like—that give each cell a sense of the communal world around it.
The brain is generally understood to be the seat of human consciousness, mental activity, motor control, and memory. It is currently understood to be a network of cells called neurons, which extend branches of themselves, called axons, outward to form connections, called synapses, with other neurons. Individual neurons fire electrochemical signals down their axial connections and, depending on chemical mediation at the synapses, encourage other neurons to receive and transfer the signal, or not. But that’s not everything going on inside the brain.
Other cells of the type called glia, which outnumber the neurons by the thousands, support this activity. Oligodendrocytes are glial cells that wrap around the axon and boost the signal, like repeaters on a telegraph wire. Microglia live between the branching nerve cells and, like brain’s own personal immune system, fight off invading bacteria and viruses. A third glial type called astrocytes hold the neurons in place, feed them nutrients, and absorb dead neurons. Astrocytes seem to have their own transmission system based on chemistry, but whether that contributes to thought and emotion or is simply part of the housekeeping is still not understood.
We know that the brain has about 100 billion neurons and they make many times their number in connections. The brain has special structures that regulate consciousness, emotion, sensory inputs, and even expectation and future orientation. But a single neuron firing a signal to another neuron is no more meaningful than a single on/off bit sitting on a computer chip and changing its state. Two neurons do not make a thought or a memory. Neither do three or four. But maybe dozens, hundreds, or thousands just might. We know from neurosurgeons that electrically stimulating a tiny patch of cells in the brain can trigger complex sensations and memories. But how many actual neurons are involved in a thought or sensation, and at what distance from the point of stimulation, are matters still poorly understood.2
We also don’t understand whether memory is an active process, requiring electrical stimulation between neurons to maintain the content, or whether some part of the memory or experience is converted into a stable, inactive chemical that can later be activated or refreshed. We do know that processing short-term experience into long-term memories requires time and the brain’s daily shutdown through the processes of sleep.3
We know—or perhaps “believe” is the better word—that the mind arises through the complexity of interconnections among the neurons. We also know that the mind has many separate and interrelated processes that work through at least three separate and distinct brain types that arose during our animal evolution. First came the brain stem, which we share with the fishes; it controls the autonomic functions—those of which we are hardly aware, like breathing—as well as raw consciousness. Next to arrive was the hind brain, or cerebellum, which controls and integrates sensory functions and motor control out in the body. And finally the cerebral cortex developed, which integrates and controls thoughts, memories, and expectations. Conscious awareness—not at the raw on/off level of the brain stem, but at the higher levels of thinking, feeling, deciding, and doing—is a complicated process. We don’t have just one thought at a time, like a locomotive moving down a track. We have a jostle of thoughts, feelings, sensations, and memories, like a school of fish moving all more or less in the same direction but each with its particular voice and function.4
The mind as brain function arises through the complexity of the neural network. And stimulation or interruption of activity in that network can cause effects in the mind. But the mind is not the same thing as the brain, in the same way that the movements of a school of fish are more than the actions of a single fish, a forest is more than the trees that compose it, and an institution like a great company or school is more than the actions of the individuals who join it. Forests have cycles of respiration, grown, age, dormancy, and environmental effects that are separate from the life cycle of any one tree.5 In the same way, the mind—once it arises—may have effects and persistence separate from the brain. At this point in our knowledge, that’s probably not the way to bet, but still …
Even the most clear-eyed, data-grounded, scientific, supernatural-denying mind must consider that the universe is more complex than we yet understand. One day, we may understand it all and resolve all questions. But for now there is room enough to wonder and to doubt. In a quantum mechanical universe which finds a mathematical basis for hypothetical particles like gravitons and their related fields that bend spacetime, for quantum entanglement among particles separated in both space and time, and for tiny, stringlike vibrations operating in obscure dimensions beyond the three we can count on our fingers, no scientific mind can say for certain that the energy of the human mind does not represent something more than mere cellular discharge.6
No one can say that some of that energy, in some form more or less coherent, does not persist after the cellular functions have ceased. It may not be completely human, nor contain every memory of your earliest childhood—although most of us can’t remember what we had for breakfast a week ago Saturday. This carried-forward residue, deprived of its human origin, may not depend on sight or hearing from eyes and ears that are no longer attached. It may not feel in all ten fingers and all ten toes, because the shape and inputs and control of the body are no longer relevant. But it may have a hint of the old “me” about it, especially as concerns basic attitudes like wonder and fear, or susceptibility to joy and anger, and dominant transactional states like loving, hating, giving, and taking. Divorced for the first time from the body and brain that formed it, that energy residue will have different sensations and new thoughts. It will be confused at first, and its perceptions may never become clear. It may not persist forever, or even for very long.7 It may dissipate with a tiny electrical “poof” and a whimper.
With such a possibility before us—distant, probably nonexistent, possibly still wishful thinking—what can we say in the face of death. Certainly, all of us on this plane of existence can say, “Goodbye!” But even the most scientific mind can also summon the grace to say, "Fare well, voyager."
1. Unless you have managed to capture some slim fraction of this externality through your writing, music, painting, photography … telling stories to your grandchildren … or some other means of communication with other human minds. And then when they—all of the people in your circle of contacts, however vast or small—have died, then the refined essence of what you thought also dies for all time.
2. Consider that axons can go a long way. For example, neuron cells located in the brain connect with your muscles by extending their axons throughout your body by way of the spinal cord and its branchings.
3. Some people even suggest that memories can be stored in or shared with other cells in the body, among the organs and tissues, carried outward from the brain by neuronal axons. Some say memories can even be transplanted to a new mind through a donated organ. While the evidence for this appears to be anecdotal, and involves the hugely evocative and emotional subject of death, the subject opens interesting possibilities for exploration.
4. For slightly more detail on brain structure and processes, see my earlier posting Death is Nothing from April 28, 2013. You might consider that a companion piece to the current meditation.
5. See Emergent Properties from August 11, 2013.
6. Note that by invoking a universe of unresolved quantum oddities which is based largely on mathematical reasoning, I am partly arguing against some of my previous positions. I am resistant to physical theories that draw most of their observations from mathematics, which is itself a construct of the human mind. See Fun With Numbers (I) and (II) from September 19 and 26, 2010.
7. And what does “forever” mean anyway? Not even the universe is destined to last forever.