Can Physics Ease the Sting of Death?

My apartment is filled with memento mori like this skull, which hangs over my couch, and reminds of the ultimate fate of all things. Those red eyes are illuminated. Cool, right?

March 14, 2024. Physicists pride themselves on their rationality, and yet they are as prone to dread as the rest of us, if not more so. They confront infinity and eternity in their day jobs, not just in the dead of night.

Moreover, physicists’ equations describe particles pushed and pulled by impersonal forces; there is no place for beauty, love, friendship, pond hockey--the things that make life worth living. From the chilly perspective of physics, the entirety of human existence, let alone an individual life, can seem terrifyingly ephemeral and pointless.

Steven Weinberg, an adamant atheist, urged us to embrace the soul-crushing implications of physics. In Dreams of a Final Theory, Weinberg says science cannot replace “the consolations that have been offered by religion in facing death.” But physicists, I suspect, cling to certain hypotheses precisely because they make mortality more bearable. Below are examples.

We Were Meant to Be Here

There is a whole class of conjectures that, like religion, give us a privileged position in the cosmic scheme of things. I call them neo-geocentric theories. They imply that we are not an accidental, incidental part of nature; we were meant to be here.

The anthropic principle suggests that the laws of nature must take the form we observe, because otherwise we would not be here to observe them. The anthropic principle is a tautology masquerading as a truth, but it is remarkably resilient.

A major reason for the endurance of the anthropic principle is the proliferation of multiverse theories, which hold that our universe is just one of many. If you buy multiverses (to which I return below), the anthropic principle helps explain why we find ourselves in this particular universe with these particular laws.

Quantum mechanics has inspired lots of we-were-meant-to-be-here proposals, because it suggests that what we observe depends on how we observe it. John Wheeler speculated that consciousness, far from being a mere side effect of matter, is an essential component of reality. The implication is that your individual consciousness might not endure, but consciousness of some kind will last as long as the universe does, maybe longer.

The Eternal Multiverse

Back to multiverse theories, which stipulate that our universe is just one among multitudes. Physicists have proposed different multiverse theories, inspired by quantum mechanics, string theory and inflation, a speculative theory of cosmic creation. What the theories have in common is a lack of evidence, or even the hope of evidence.

What explains their popularity? Here’s my guess: Physicists are freaked out by the mortality of our little universe. What was born must die; the big bang theory says our cosmos was born 14 or so billion years ago, and it will die at some unspecified time in the far future. But even though our little, local cosmos might be doomed, the multiverse, like God, is eternal; it had no beginning, it will have no end. Doesn’t that make you feel better?

Everything Is Conserved

Then there are conservation laws. Energy, for example, can take many forms—kinetic, potential, electrical, thermal, gravitational, nuclear--and it can change from one form into another. Matter can become energy, and vice versa, as Einstein stipulated in E = mc2. But if you add up all the kinds of energy at any given instant, that sum remains constant.

Other conservation laws apply to angular momentum, charge and “information.” In what way are conservation laws consoling? Because to be human is to know loss. When we look at the world, and at our own faces in the mirror, we see the terrible transience of things. All we love will vanish sooner or later. It is reassuring to know that, on some level, things stay the same. According to conservation laws, there are no endings or beginnings, only transformations.

The Upside of Determinism

Determinism, physics-style, assumes that reality is strictly physical. Everything that happens, including our choices, results from physical forces, like gravity, pushing and pulling physical objects, like protons. Moreover, every present moment is associated with a singular past and singular future. I don’t like determinism, because it subverts free will and makes us more likely to accept that the way things are is the way they must be.

But I can see the upside of determinism. The world often seems disturbingly out of control. We have the sense that at any moment bad things might happen on scales small and large. A truck might strike you as you cross the street, absent-mindedly brooding over the solipsism problem. A mutant virus might suddenly emerge from who-knows-where and kill millions of people. Millions of your fellow citizens might fall for a thuggish conman. A nearby supernova might bathe the earth in lethal radiation.

We desperately want to believe that, beneath the apparent randomness, someone, something, is in control. God, for many people, is the tough but fair chief executive running this seemingly chaotic, cosmic corporation. It’s hard for us to see Her/His/Its/Their plan, but She/He/It/They surely knows what She/He/It/They is doing.

If you find the God hypothesis implausible, then physics-based determinism might serve as a substitute. According to this perspective, the universe isn’t careening wildly into an unknowable future. It is gliding serenely, undeviatingly along a rigid track laid down at the beginning of time. As a free-will fanatic, I don’t find this perspective comforting, but I understand why others do. If determinism is true, there’s nothing you can do to change things, so sit back and enjoy the ride. Everything is as it should be. Must be.

I don’t find any physics hypotheses very consoling. I wish I did. I’ve been brooding over death a lot lately, because of my advancing age and the precarious state of the world. I have my consolations. I’m a writer and father, so I fantasize about people reading my books after I’m gone, and I envision my son and daughter living good, fulfilling lives, and possibly having children of their own.

These wishful visions require civilization’s continuation, so I tell myself that civilization, in spite of its manifest flaws, is pretty good and getting better. I manage to sustain this hope, on good days, and to keep my fear of dissolution, personal and collective, at bay.

Further Reading:

Is “Information” Eternally Conserved?

I dwell on death and physics in My Quantum Experiment (which you can read for free on this website) and Pay Attention: Sex Death, and Physics.

See also “Consolations of Physics,” my 2021 conversation with physicist and determinist Sabine Hossenfelder.

Self-plagiarism alert: This is much, much better version of a paywalled Scientific American column.