Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe

by Brian Greene

The assignment was to develop a theory of why we humans do what we do, but each time I started writing, the project seemed decidedly nebulous. If you clothed reasonable-sounding ideas in the right language it seemed that you could pretty much make it up as you went along.

“Man is the only being that knows death; all others become old, but with a consciousness wholly limited to the moment which must seem to them eternal,” knowledge that instills the “essentially human fear in the presence of death.” Spengler concluded that “every religion, every scientific investigation, every philosophy proceeds from it.”3

Jean-Paul Sartre went farther, noting that life itself is drained of meaning “when you have lost the illusion of being eternal.”5 The suggestion, then, threading its way through these and other thinkers who followed, is that much of human culture—from artistic exploration to scientific discovery—is driven by life reflecting on the finite nature of life.

Eternity, as these preoccupations demonstrate, has a powerful pull on the mind aware that its material duration is limited.

We emerge from laws that, as far as we can tell, are timeless, and yet we exist for the briefest moment of time. We are guided by laws that operate without concern for destination, and yet we constantly ask ourselves where we are headed. We are shaped by laws that seem not to require an underlying rationale, and yet we persistently seek meaning and purpose.

The unfolding of any given life is beyond prediction. The final fate of any given life is a foregone conclusion.

“Man is literally split in two: he has an awareness of his own splendid uniqueness in that he sticks out of nature with a towering majesty, and yet he goes back into the ground a few feet in order blindly and dumbly to rot and disappear forever.”

However, unlike the opposable thumb or upright gait—inherited physiological features tightly linked to specific adaptive behaviors—many of the brain’s inherited characteristics mold predilections rather than definitive actions. We are influenced by these predispositions but human activity emerges from a comingling of behavioral tendencies with our complex, deliberative, self-reflective minds.

As our trek across time will make clear, life is likely transient, and all understanding that arose with its emergence will almost certainly dissolve with its conclusion. Nothing is permanent. Nothing is absolute. And so, in the search for value and purpose, the only insights of relevance, the only answers of significance, are those of our own making. In the end, during our brief moment in the sun, we are tasked with the noble charge of finding our own meaning.

The second law describes a fundamental characteristic inherent in all matter and energy, regardless of structure or form, whether animate or inanimate. The law reveals (loosely, again) that everything in the universe has an overwhelming tendency to run down, to degrade, to wither.

You should expect to encounter high-entropy states. Because such states can be realized by a great many different arrangements of the constituent particles, they’re typical, pedestrian, easily configured, a dime a dozen. By contrast, if you encounter a low-entropy state it should command your attention. Low entropy means there are far fewer ways the given macrostate can be realized by its microscopic ingredients, and so such configurations are hard to come by, they’re unusual, they’re carefully arranged, they’re rare.

Just as you’d suspect there’s a reason beyond mere chance that a hundred pennies on your dining room table are all heads (such as someone judiciously flipped over each coin that landed tails), you should seek an explanation beyond mere chance for any low-entropy configurations you encounter.

whereas the first law of thermodynamics declares that the quantity of energy is conserved over time, the second law declares that the quality of that energy deteriorates over time.

In short, entropy rides the wave of flowing heat.

The entropic two-step lies at the heart of how a universe heading toward ever-greater disorder can nevertheless yield and support ordered structures like stars, planets, and people. A theme we will encounter repeatedly is that when energy flows through a system—like the energy from burning coal flowing through the steam, driving work, and then exiting to the surrounding environment—it carries away entropy and can thus sustain or even produce order in its wake. It is this entropic dance that will choreograph the rise of life and mind, as well as most everything that minds deem to matter.

As surprising as it is remarkable, regions containing concentrated energy and order (stars being the archetypal example) are a natural consequence of the universe diligently toeing the second law’s line and becoming ever more disordered. Indeed, such pockets of order prove to be catalysts that facilitate the universe, over the long run, to reach its entropic potential. Along the way, and as part of this entropic progression, they also facilitate the emergence of life.

It is only by comparison with the demonstrably incorrect classical view—the view we humans discovered first because it’s both simpler and extraordinarily accurate on the scales accessible to human senses—that quantum reality seems hazy. It is actually the classical perspective that provides an approximate and hence imprecise view of the true quantum reality.

But in asking a question of ultimate origin, we are seeking an answer that requires no antecedent, an answer that does not shift the question one step further back, an answer that is immune to the follow-on questions “Why were things this way instead of that?” or “Why these laws instead of those?” No explanation yet proposed has achieved this or even come close.

Since all of these machinations would have taken place during a period of prehistory, before the rapid expansion of space we call the big bang, there was no one hanging around, arms crossed and shoe tapping, waiting for inflationary expansion to ignite. So let the inflationary preshow run as long as it takes. It is only when the statistical fluke of a uniform inflaton patch happens to happen that things finally change: the big bang is sparked, space inflates, and the cosmological performance begins.

But—and this is remarkable and remarkably important—when gravity is directing the show, the conclusion is reversed. As heat flows out from the core, the core gets hotter and the shell gets cooler.

The manner in which the second law’s directive is carried out thus depends sensitively on the force of gravity. When there’s enough gravity—enough sufficiently concentrated stuff—ordered structures can form.

The upshot, anthropomorphized, is that the universe cleverly leverages the gravitational and nuclear forces to wrest a cache of untapped entropy that’s locked up inside of its material constituents. Without gravity, particles that are uniformly dispersed, like an aroma that has filled your house, have attained the highest entropy available. But with gravity, particles that are squeezed into massive and dense balls supported by nuclear fusion drive the entropy tally yet higher.

More often than not, physicists are reductionists and so tend to look beneath complex phenomena for explanations that rely on properties and interactions of simpler constituents. Whereas biologists often define life by its core activities—life imbibes raw materials for powering self-sustaining functions, eliminates waste generated by the process, and in the most successful instances reproduces—Schrödinger sought an answer to “What is life?” that would draw on life’s fundamental physical underpinnings.

Life is recognizable from the collective behavior, the large-scale organization, the overarching coordination of an enormous number of particulate constituents—even a single cell contains more than a trillion atoms. Seeking insight into life by homing in on fundamental particles is akin to experiencing a Beethoven symphony instrument by instrument, note by single note.

Deep mysteries call for clarity delivered through a collection of nested stories. Whether reductionist or emergent, whether mathematical or figurative, whether scientific or poetic, we piece together the richest understanding by approaching questions from a range of different perspectives.

the questions we ask determine the stories that provide the most useful answers. It’s a narrative structure that capitalizes on one of nature’s most fortuitous qualities. At each scale the universe is coherent.

life is one more means the universe employs to release the entropy potential locked within matter.

Scientists have yet to determine the origin of life, but our discussion has made clear that the question is a three-parter. How did the genetic component of life—the capacity to store, utilize, and replicate information—come to be? How did the metabolic component of life—the capacity to extract, store, and utilize chemical energy—come to be? How did the packaging of genetic and metabolic molecular machinery into self-contained sacks—cells—come to be? The story of life’s origin requires definitive answers to these questions, but even without a complete understanding we can turn to an explanatory framework—Darwinian evolution—that will almost certainly be an integral part of that future narrative.

Life is physics orchestrated.

While a complete reductionist description would provide a scientific bedrock, other descriptions of reality, other stories, provide insights that many deem more relevant because they are closer to experience.

Imagine you see the car’s sleek red exterior, feel the smooth ergonomic shape of the door handles, smell the unmistakable new car aroma, and so on. Intuitively, we think of these as direct experiences of an external reality, but as we have known for centuries they are not. Modern science makes this explicit. Red light reflecting off the Ferrari’s surface is an electric field that oscillates at roughly four hundred trillion times each second at right angles to a similarly oscillating magnetic field, all traveling toward you at three hundred million meters per second. That is the physics of red light, and that is the stimulus your eyes encounter.30 Notice that there is no “red” in the physics description. Red happens when the electromagnetic field enters your eyes, tickles light-sensitive molecules in your retina, and generates an impulse carried to your brain’s visual cortex, which specializes in visual information processing and interprets the signal. Red is a human construct that happens deep inside your head. And that new car smell? A similar story. The seats, carpet, and plastic wrap off-gas molecules that permeate the car’s interior. There is no new car smell until those molecules waft into your nostrils, brush up against receptor neurons on your olfactory epithelium, and generate an impulse that fires along your olfactory nerve toward your olfactory bulb, which relays the processed signal to various neurological structures for interpretation. As with red, the only pla...

The hard problem seems hard—consciousness seems to transcend the physical—only because our schematic mental models suppress cognizance of the very brain mechanics that connect our thoughts and sensations to their physical underpinnings.

Much like Newton, Schrödinger leaves no room for free will.

Understandably. A gap in scientific knowledge is an alluring place to hide something deeply valued, at least until the gap is closed.

To be free requires that we are not marionettes whose strings are pulled by physical law. Whether the laws are deterministic (as in classical physics) or probabilistic (as in quantum physics) is of deep significance to how reality evolves and to the kinds of predictions science can make. But for assessing free will, the distinction is irrelevant.

Our choices seem free because we do not witness nature’s laws acting in their most fundamental guise; our senses do not reveal the operation of nature’s laws in the world of particles.

Some of the most thoughtful of these collections are then bewildered by the conflict between the freedom of will they experience and the unyielding control of physical law they recognize. But the fact is there is no conflict because there is no transcending of physical law. There can’t be. Instead, the collections of particles need to reassess their powers, focusing not on the laws that govern particles themselves but on the high-level, thoroughly complex, and extraordinarily rich behaviors each collection of particles—each individual—can exhibit and experience. And with that reorientation, the particle collections can tell an illuminating story of wondrous behaviors and experiences, suffused with wills that feel free and speak as though they have autonomous control, and yet are fully governed by the laws of physics.

Sometime in the far future, if we finally play host to visitors from a distant world, our scientific narratives will contain truths they will have likely discovered too, and so will have little to offer. Our human narratives, as with Picard and the Tamarians, will tell them who we are.

Evolutionary success in a social setting primed our brains to attribute common experiences to the actions of fellow beings. When lightning struck or the floods came or the earth shook, we continued to imagine that a thinking being was responsible. Faced with it all, we can imagine our forebears implicitly acknowledging the limits of their influence in an uncertain world and in response conjuring characters inhabiting an invisible realm that would wield the very powers they lacked.

Religion is story, enhanced by doctrines, rituals, customs, symbols, art, and behavioral standards. By conferring an aura of the sacred upon collections of such activities and by establishing an emotional allegiance among those who practice them, religion extends the club of kinship. Religion provides membership to unrelated individuals who thus feel part of a strongly bound group. Even though our genetic overlap is minimal, we are primed to work together and protect one another because of our religious attachment. Such cooperation matters. Deeply. As we have seen, humans prevailed in no small part because our species has the capacity to pool brain and brawn, to live and work in groups, to divvy up responsibilities and effectively meet the needs of the collective. The greater social cohesion of those in a religiously bound group would have made them a more formidable force in the ancestral world, and according to this line of argument, securing an adaptive role for religious affiliation.

On average, the fines issued by the mortality-primed judges were nine times that of the control group.22

Religious systems became increasingly organized as adherents set down stories, culled insights, and synthesized directives that, having been channeled through anointed prophets and passed orally from one generation to the next, had garnered a stamp of the sacred.

But ancient hymns and verse, imaginative stories of the thousand-headed Purusha dismembered to create the sun, earth, and moon, as well as the many other evocative and lofty offerings, do not account for the origin of the universe. The words reflect our pattern-seeking, explanation-craving, survival-attuned minds developing a vivid story to provide a symbolic framework for living—how we came to be, how we should behave, the consequences of our actions, and the nature of life and death.

But, I continued, sometimes we go overboard. Sometimes, our naturally selected pattern detectors are so primed, so ready to announce that a signal has been found, that they see patterns and envision correlations that are not there. Sometimes we assign meaning to the meaningless. From basic math we know that on average, one out of every four times you’ll correctly guess a card’s suit; one out of every thirteen times, you’ll guess its rank. But that pattern reveals nothing about telepathic ability. Once in a blue moon—well, less often than that—you’ll randomly walk the field and find your matching card, but that says nothing about the fulfillment of dreams. How often, I asked, do you notice that a remarkable coincidence did not happen?

Myth did not supplicate for belief. It did not elicit a crisis of faith that through painstaking deliberation was resolved by its beholders. Myth provided a poetic schema, a metaphorical mind-set, which became inseparable from the reality it illuminated.

But there is an enormous gulf between mere compatibility and explanatory necessity. We invoke the equations of Einstein and Schrödinger, the evolutionary framework of Darwin and Wallace, the double helix of Watson and Crick, and a long list of other scientific achievements not because they are compatible with our observations, which of course they are, but because they provide a powerful, detailed, and predictive explanatory structure for understanding our observations. On this measure, religious doctrines do not register;

Nevertheless, religious doctrine (or even that of Ramtha) can remain fully part of rational discourse if we are willing to move away from literalism, cherry-picking scripture, disregarding elements we find offensive or outmoded, interpreting stories and statements poetically or symbolically or, yet more simply, as elements of a fictional account.

Beauty, in this analysis of sexual selection, is a good deal more than skin-deep. Beauty amounts to publicly available credentials attesting to a potential mate’s adaptive fitness.

Evolution thus generates a collection of self-reinforcing feedback loops that renders pleasurable those behaviors that enhance fitness. In Pinker’s view, the arts cut the feedback loops, sever adaptive benefits, and directly stimulate our pleasure centers, yielding gratifying experiences that from an evolutionary perspective are unearned.

But a mind that becomes accustomed to freely crossing the boundary between what’s real and what’s imagined—all the while keeping clear tabs on which is which—is a mind that becomes adept at breaking the bonds of conventional thinking. Such a mind is primed for innovation and ingenuity.