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

by Brian Greene

As cultural anthropologist Ernest Becker maintained, we are under a constant existential tension, pulled toward the sky by a consciousness that can soar to the heights of Shakespeare, Beethoven, and Einstein but tethered to earth by a physical form that will decay to dust.

According to Becker, we are impelled by such awareness to deny death the capacity to erase us. Some soothe the existential yearning through commitment to family, a team, a movement, a religion, a nation—constructs that will outlast the individual’s allotted time on earth. Others leave behind creative expressions, artifacts that extend the duration of their presence symbolically.

Such self-reflective beings have naturally wondered what consciousness is and how it arose: How can a swirl of mindless matter think and feel?

The brain, after all, is but another biological structure evolving via selection pressures, and it is the brain that informs what we do and how we respond.

Through our creative capacities we have developed formidable defenses against what would otherwise have been debilitating disquiet.

The future we tend to envision, even if only implicitly, is one that’s populated by the kinds of things we care about.

And this raises a question that will ride along with us throughout the journey: Can conscious thought persist indefinitely? Or might the thinking mind, like the Tasmanian tiger or the ivory-billed woodpecker, be something sublime that rises up for a period but then goes extinct?

But the most straightforward reading suggests that life, and intelligent life in particular, is ephemeral. The interval on the cosmic timeline in which conditions allow for the existence of self-reflective beings may well be extremely narrow. Take a cursory glance at the whole shebang, and you might miss life entirely.

We mourn our transience and take comfort in a symbolic transcendence, the legacy of having participated in the journey at all. You and I won’t be here, but others will, and what you and I do, what you and I create, what you and I leave behind contributes to what will be and how future life will live. But in a universe that will ultimately be devoid of life and consciousness, even a symbolic legacy—a whisper intended for our distant descendants—will disappear into the void. Where, then, does that leave us?

Though governed by elegant mathematical laws that allow for all manner of wondrous physical processes, the universe will play host to life and mind only temporarily. If you take that in fully, envisioning a future bereft of stars and planets and things that think, your regard for our era can appreciate toward reverence.

And that is the feeling I had experienced at Starbucks. The calm and connection marked a shift from grasping for a receding future to the feeling of inhabiting a breathtaking if transient present.

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 fact that we can use mathematics to describe what we think took place nearly fourteen billion years ago, and from that successfully predict what powerful telescopes should now see, well, it is breathtaking. Sure, profound questions abound, like what or who created space and time, and what or who imposed the guiding grip of mathematics, and what or who is responsible for there being anything at all, but even with all that left unanswered we’ve gained powerful insight into the cosmic unfolding.

A hundred pennies with all heads has low entropy and yet admits an immediate explanation—instead of dumping the coins on the table, someone carefully arranged them. But what or who arranged the special low-entropy configuration of the early universe?

Indeed, in an epilogue to What Is Life? touching on consciousness, Schrödinger raised some eyebrows (and lost his first publisher) when he invoked the Hindu Upanishads to suggest that we are all part of an “omnipresent, all-comprehending eternal self,” and the freedom of will we each exert reflects our divine powers.

This will lead us to examine life from the broadly applicable thermodynamic perspective developed in previous chapters, making clear that living things share a deep kinship not just with one another but with stars and steam engines too: life is one more means the universe employs to release the entropy potential locked within matter.

Grind up anything previously alive, pry apart its complex molecular machinery, and you’ll find an abundance of the same six types of atoms: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur, a collection of elements students sometimes remember with the acronym SPONCH

Roughly fifty to one hundred million years after its birth, earth likely collided with a Mars-sized planet called Theia, which would have vaporized the earth’s crust, obliterated Theia, and blown a cloud of dust and gas thousands of kilometers into space. In time, that cloud would have clumped up gravitationally to form the moon, one of the larger planetary satellites in the solar system and a nightly reminder of that violent encounter. Another reminder is provided by the seasons. We experience hot summers and cold winters because earth’s tilted axis affects the angle of incoming sunlight, with summer being a period of direct rays and winter being a period of oblique ones. The smashup with Theia is the likely cause of earth’s cant.

The details vary, but water’s asymmetric charge arrangement makes it an uncanny solvent. Wash your hands, even without soap, and water’s electrical polarity will be hard at work, dissolving foreign matter and carrying it away.

Well beyond its utility in personal hygiene, water’s capacity to grab hold of and ingest substances is indispensable to life.

All life codes the instructions for building proteins in the same way.25

First, seeing the code makes the concept of cellular software explicit. Given a segment of DNA, we can read off the instructions which direct the cell’s inner workings, a sophisticated coordination wholly absent in inanimate matter. Second, seeing the code demonstrates what biologists mean when they call it universal. Every molecule of DNA, whether from seaweed or Sophocles, encodes the information needed to build proteins in the same way. That is the unity of life’s information.

The universal solution life has come up with, a complex sequence of processes taking place right now inside you and me and, as far as we know, all else that lives, ranks among nature’s most astonishing accomplishments. Life extracts energy from the environment through a type of slow chemical burning and stores that energy by charging up biological batteries built into all cells. These cellular battery packs then provide a steady source of electricity that cells use to synthesize molecules tailor-made for transporting and delivering energy to every cellular component.

From the perspective of physics, it’s worth emphasizing how surprising this all is. Energy is the coin that pays for all comings and goings throughout the cosmos, a coin minted in a wide range of currencies and earned through an even wider range of callings. One currency is nuclear energy, generated by fission and fusion among a wealth of atomic species; electromagnetic energy is another, generated by pushes and pulls among a wealth of charged particles; gravitational energy is another still, generated by interactions among a wealth of massive bodies. And yet of all the innumerable processes, life on planet earth leverages one and only one energy mechanism: a specific sequence of electromagnetic chemical reactions in which electrons engage in a downward-directed sequence of jumps, starting with food or water and ending with the clutching embrace of oxygen.

Some who encounter the wonder of the eye, the capacities of the brain, or the complexity of the cellular energy mechanisms will conclude that these systems could not have evolved without a guiding intelligence. And that conclusion would be justified if evolutionary development took place over familiar timescales. It didn’t.

Nature is not in a hurry and does not need to meet a bottom line. The cost of innovating by small random changes is a cost nature can bear.30

Understanding would deepen if we could identify the physical conditions required for generating subjective experiences, a task central to the theory of consciousness we now consider.

That the brain is a crenellated, moist, information-processing collection of cells is uncontroversial.

Even focusing more narrowly on the car’s color, note that your experience is decidedly not one of a colorless Ferrari that your mind subsequently paints red. Nor is it of an abstract red environment that your mind subsequently shapes into a Ferrari. Although shape information and color information activate different parts of the visual cortex, your conscious experience of the Ferrari’s shape and color are inseparable. You experience them as one. This, according to Tononi, is an intrinsic quality of consciousness: the information threading through conscious experience is tightly stitched together.

Your experience of conscious awareness resides in a biological brain, but according to Tononi and his math, a sufficiently high value of ф, whether contained in neural synapses or neutron stars, would be consciously aware.

But here is the difference, familiar to many yet still deeply shocking: in the ordinary classical description, after you flip the coin but before you look, the coin is either heads or tails, you simply don’t know which. By contrast, in the quantum description, prior to examining the whereabouts of a particle like an electron that has a 50 percent chance of being here and a 50 percent chance of being there, the particle is not either here or there. Instead, quantum mechanics says the particle is hovering in a fuzzy mixture of being both here and there.

The problem is, the more we’ve worked, the weirder things have become. There is nothing in the quantum equations that shows how reality transitions from the fuzzy mixture of many possibilities to the single definite outcome you witness upon undertaking a measurement.

The challenge, known as the quantum measurement problem, is to resolve the puzzling disparity between the fuzzy quantum reality described by the equations and the sharp familiar reality you consistently experience.37

As far back as the 1930s, physicists Fritz London and Edmond Bauer,38 and a few decades later Nobel laureate Eugene Wigner,39 suggested that consciousness might be the key. After all, the puzzle becomes puzzling only when you report on your conscious experience of a definite reality, yielding a mismatch between what you say and what the mathematics of quantum mechanics predicts.

Consciousness would thus be an intimate participant in quantum physics, dictating that as the world evolves all but one of the many possible futures are eliminated, either from reality itself or at least from our cognitive awareness.

You can see the appeal. Quantum mechanics is mysterious. Consciousness is mysterious. How fun to imagine that their mysteries are related, or are the same mystery, or that each mystery resolves that of the other.

Few of us take pride in how our pancreas produces chymotrypsin or the trigeminal nerve network facilitates a sneeze. We don’t feel a vested interest in our autonomic processes. If I’m asked who I am, I turn to the thoughts, sensations, and memories that I can access with my mind’s eye or interrogate with my inner voice. Everyone’s pancreas synthesizes chymotrypsin and everyone sneezes but, I like to imagine, there’s something deeply, fully, and intrinsically me in what I think, in what I feel, in what I do.

So my focus here is not on predicting your next move. My focus is on the existence of laws that govern your next move. And even though the calculations exceed our current abilities, there has never been the slightest mathematical, experimental, or observational indication that these laws exert anything but total control. Unexpected and impressive phenomena can surely emerge from the coordinated motion of a great many microscopic ingredients—typhoons to tigers—but all evidence suggests that were we able to work out the math for such large groups of interacting particles, we would be able to predict their collective behaviors.

The quantum equations lay out many possible futures, but they deterministically chisel the likelihood of each in mathematical stone. Much like Newton, Schrödinger leaves no room for free will.

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.

To sum up: We are physical beings made of large collections of particles governed by nature’s laws.

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. Our senses and our reasoning focus on everyday human scales and actions: we think about the future, compare courses of action, and weigh possibilities.

Human freedom is not about willed choice. Everything science has so far revealed has only strengthened the case that such volitional intercession in the unfolding of reality does not exist. Instead, human freedom is about being released from the bondage of an impoverished range of response that has long constrained the behavior of the inanimate world.

Giving up the traditional concept of free will may still seem to require relinquishing much of what we value. If the unfolding of reality, including that of sentient beings, is set by physical law, do our behaviors matter? Can we simply sit back, do nothing, and let physics run its course? Is there any place for individuality? How can capacities we greatly value, like learning and creativity, play any role?

Our sense of who we are, the capacities we have, and the freedom of will we seemingly exert all emerge from the particles moving through our heads. Fiddle with the particles, and those familiar qualities can fall away. It’s an experience that helped align my rational grasp of the physics with my intuitive sense of the mind.

We need to recognize that although the sensation of free will is real, the capacity to exert free will—the capacity for the human mind to transcend the laws that control physical progression—is not.

Is mathematics a language humankind developed to describe patterns we encounter? Or is mathematics the source of reality, rendering the world’s patterns the expression of mathematical truth? My romantic sensibilities lean toward the latter. How wonderful to imagine that our mathematical manipulations touch the very foundation of reality.

How is it that within a few short years after birth, without formal instruction, we become fluent in one or even multiple languages? Are our brains specifically configured to acquire language, or does cultural immersion together with our general propensity to learn new things offer an adequate explanation?

Why do we have language? Did evolution directly select for language because it provides a survival advantage, or is language a by-product of other evolutionary developments like larger brain size? And across all these thousands of years, what in the world have we all been talking about? And why?

Chomsky has proposed that a singular neurobiological event, a “slight rewiring of the brain” perhaps eighty thousand years ago, may have resulted in our ancestors acquiring this capacity, sparking a cognitive big bang that blasted language clear across the species.11