This Explains Everything

by Mr. John Brockman

  I highlight monogamy here because, of the many topics to which reflective equilibrium can be usefully applied, Western society’s position on monogamy is at the most critical juncture. Monogamy today compares with heterosexuality not too many decades ago, or tolerance of slavery 150 years ago. Quite a lot of people depart from it, a much smaller minority actively advocate the acceptance of departure from it, but most people advocate it and disparage the minority view. Why is this the “critical juncture”? Because it is the point at which enlightened thought-leaders can make the greatest difference to the speed with which the transition to the morally inescapable position occurs.

  First let me make clear that I refer here to sex and not (necessarily, anyway) to deeper emotional attachments. Whatever one’s views or predilections concerning the acceptability or desirability of having deep emotional attachments with more than one partner, fulfillment of the responsibilities they entail tends to take a significant proportion of the twenty-four hours of everyone’s day. The complications arising from this inconvenient truth are a topic for another time. In this essay, I focus on liaisons casual enough (whether or not repeated) that availability of time is not a major issue.

  An argument from reflective equilibrium always begins with identification of the conventional views, with which one then makes a parallel. In this case, it’s all about jealousy and possessiveness. Consider chess, or drinking. These are rarely solitary pursuits. Now, is it generally considered reasonable for a friend with whom one sometimes plays chess to feel aggrieved when one plays chess with someone else? Indeed, if someone exhibited possessiveness in such a matter, would they not be viewed as unacceptably overbearing and egotistical?

  My claim is probably obvious by now. It is simply that there is nothing about sex that morally distinguishes it from other activities performed by two (or more) people collectively. In a world no longer driven by reproductive efficiency, and presuming that all parties are taking appropriate precautions in relation to pregnancy and disease, sex is overwhelmingly a recreational activity. What, then, can morally distinguish it from other recreational activities? Once we see that nothing does, reflective equilibrium forces us to one of two positions: Either we start to resent the temerity of our regular chess opponents playing others, or we cease to resent the equivalent in sex.

  My prediction that monogamy’s end is extremely nigh arises from my reference to reproductive efficiency above. Every single society in history has seen a precipitous reduction in fertility following its achievement of a level of prosperity that allowed reasonable levels of female education and emancipation. Monogamy is virtually mandated when a woman spends her entire adult life with young children underfoot, because continuous financial support cannot otherwise be ensured. But when it is customary for those of both sexes to be financially independent, this logic collapses. This is especially so for the increasing proportion of men and women who choose to delay having children until middle age (if then).

  I realize that rapid change in a society’s moral compass needs more than the removal of influences maintaining the status quo; it also needs an active impetus. What is the impetus in this case? It is simply the pain and suffering that arises when the possessiveness and jealousy inherent in the monogamous mind-set butt heads with the asynchronous shifts of affection and aspiration inherent in the response of human beings to their evolving social interactions. Gratuitous suffering is anathema to all. Thus, the realization that this particular category of suffering is wholly gratuitous has not only irresistible moral force (via the principle of reflective equilibrium) but also immense emotional utility.

  The writing is on the wall.

  BOLTZMANN’S EXPLANATION OF THE SECOND LAW OF THERMODYNAMICS

  LEONARD SUSSKIND

  Felix Bloch Professor of Physics, Stanford; director, Stanford Institute for Theoretical Physics; author, The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics

  “What is your favorite deep, elegant, or beautiful explanation?” That’s a tough question for a theoretical physicist; theoretical physics is all about deep, elegant, beautiful explanations, and there are many to choose from.

  Personally, my favorites are explanations that get a lot for a little. In physics, that means a simple equation or a very general principle. I have to admit, though, that no equation or principle appeals to me more than Darwinian evolution, with the selfish-gene mechanism thrown in. To me, it has what the best physics explanations have: a kind of mathematical inevitability. But there are many people who can explain evolution better than I, so I will stick to what I know best.

  The guiding star for me, as a physicist, has always been Ludwig Boltzmann’s explanation of the second law of thermodynamics—the law that says that entropy never decreases. To the physicists of the late 19th century, this was a very serious paradox. Nature is full of irreversible phenomena—things that easily happen but could not possibly happen in reverse order. However, the fundamental laws of physics are completely reversible: Any solution of Newton’s equations can be run backwards and it’s still a solution. So if entropy can increase, the laws of physics say it must be able to decrease. But experience says otherwise. For example, if you watch a movie of a nuclear explosion in reverse, you know very well that it’s fake. As a rule, things go one way and not the other. Entropy increases.

  What Boltzmann realized is that the second law—entropy never decreases—is not a law in the same sense as Newton’s law of gravity or Faraday’s law of induction. It’s a probabilistic law that has the same status as the following obvious claim: If you flip a coin a million times, you will not get a million heads. It simply won’t happen. But is it possible? Yes, it is; it violates no law of physics. Is it likely? Not at all. Boltzmann’s formulation of the second law was very similar. Instead of saying entropy does not decrease, he said entropy probably doesn’t decrease. But if you wait around long enough in a closed environment, you will eventually see entropy decrease; by accident, particles and dust will come together and form a perfectly assembled bomb. How long? According to Boltzmann’s principles, the answer is the exponential of the entropy created when the bomb explodes. That’s a very long time, a lot longer than the time it takes to flip a million heads in a row.

  I’ll give you a simple example to see how it’s possible for things to be more probable one way than the other, despite both being possible. Imagine a high hill that comes to a narrow point—a needle point—at the top. Now imagine a bowling ball balanced at the top of the hill. A tiny breeze comes along. The ball rolls off the hill, and you catch it at the bottom. Next, run it in reverse: The ball leaves your hand, rolls up the hill, and with infinite finesse, comes to the top—and stops! Is it possible? It is. Is it likely? It is not. You would have to have almost perfect precision to get the ball to the top, let alone to have it stop dead-balanced. The same is true with the bomb. If you could reverse every atom and particle with sufficient accuracy, you could make the explosion products reassemble themselves. But a tiny inaccuracy in the motion of just one single particle and all you would get is more junk.

  Here’s another example: Drop a bit of black ink into a tub of water. The ink spreads out and eventually makes the water gray. Will a tub of gray water ever clear up and produce a small drop of ink? Not impossible, but very unlikely.

  Boltzmann was the first to understand the statistical foundation for the second law, but he was also the first to understand the inadequacy of his own formulation. Suppose you came upon a tub that had been filled a zillion years ago and had not been disturbed since. You notice the odd fact that it contains a somewhat localized cloud of ink. The first thing you might ask is, What will happen next? The answer is that the ink will almost certainly spread out more. But by the same token, if you ask what most likely took place a moment before, the answer would be the same: It was probably more spread out a moment ago than it is now. The most likely explanation would be that the ink blob is just a momentary fluctuation. />
  Actually, I don’t think you’d come to that conclusion at all. A much more reasonable explanation is that, for reasons unknown, the tub started not so long ago with a concentrated drop of ink, which then spread. Understanding why ink and water go one way becomes a problem of “initial conditions.” What set up the concentration of ink in the first place?

  The water and ink is an analogy for the question of why entropy increases. It increases because it’s most likely that it will increase. But the equations say that it’s also most likely that it increases toward the past. To understand why we have this sense of direction, one must ask the same question Boltzmann did: Why was the entropy very small at the beginning? What created the universe in such a special low-entropy way? That’s a cosmological question we are still very uncertain about.

  I began telling you what my favorite explanation is, and I ended up telling you what my favorite unsolved problem is. I apologize for not following the instructions. But that’s the way of all good explanations. The better they are, the more questions they raise.

  THE DARK MATTER OF THE MIND

  JOEL GOLD

  Psychiatrist; clinical associate professor of psychiatry, NYU School of Medicine

  There are people who want a stable marriage yet continue to cheat on their wives.

  There are people who want a successful career yet continue to undermine themselves at work.

  Aristotle defined man as a rational animal. Contradictions like these show that we are not. All people live with the conflicts between what they want and how they live. For most of human history we had no way to explain this paradox, until Freud’s discovery of the unconscious resolved it. Before Freud, we were restricted to our conscious awareness when looking for answers regarding what we knew and felt. All we had to explain incompatible thoughts, feelings, and motivations was limited to what we could access in consciousness. We knew what we knew and we felt what we felt. Freud’s elegant explanation postulated a conceptual space, not manifest to us, where irrationality rules. This aspect of the mind is not subject to the constraints of rationality, such as logical inference, cause and effect, and linear time. The unconscious explains why presumably rational people live irrational lives.

  Critics may take exception as to what Freud believed resides in the unconscious—drives both sexual and aggressive, defenses, conflicts, fantasies, affects, and beliefs—but no one would deny its existence; the unconscious is now a commonplace. How else to explain our stumbling through life, unsure of our motivations, inscrutable to ourselves? I wonder what a behaviorist believes is at play while he is in the midst of divorcing his third astigmatic redhead.

  The universe consists primarily of dark matter. We can’t see it, but it has an enormous gravitational force. The conscious mind—much like the visible aspect of the universe—is only a small fraction of the mental world. The dark matter of the mind, the unconscious, has the greatest psychic gravity. Disregard the dark matter of the universe and anomalies appear. Ignore the dark matter of the mind and our irrationality is inexplicable.

  “THERE ARE MORE THINGS IN HEAVEN AND EARTH . . . THAN ARE DREAMT OF IN YOUR PHILOSOPHY.”

  ALAN ALDA

  Actor, writer, director; host of PBS program The Human Spark; author, Things I Overheard While Talking to Myself

  That doesn’t sound like an explanation, but I take it that way. For me, Hamlet’s admonition explains the confusion and uncertainty of the universe (and, lately, the multiverse). It urges us on when, as they always will, our philosophies produce anomalies. It answers the unspoken question, “WTF?” With every door into nature we nudge open, 100 new doors become visible, each with its own inscrutable combination lock. It is both an explanation and a challenge, because there’s always more to know.

  I like the way it endlessly loops back on itself. Every time you discover a new thing in heaven or earth, it becomes part of your philosophy, which will eventually be challenged by new new things.

  Like all explanations, of course, it has its limits. Hamlet says it to urge Horatio to accept the possibility of ghosts. It could just as well be used to prompt belief in UFOs, astrology, and even God—as if to say that that something is proved to exist by the very fact that you can’t disprove it exists.

  Still, the phrase can get us places. Not as a taxi to the end of thinking but as a passport to exploration. These words of Hamlet’s are best thought of as a ratchet—a word earthily beautiful in sound and meaning: Keep moving on, but preserve what works. We need Einstein for GPS, but we can still get to the moon with Newton.

  AN UNRESOLVED (AND THEREFORE UNBEAUTIFUL) REACTION TO THE EDGE QUESTION

  REBECCA NEWBERGER GOLDSTEIN

  Philosopher, novelist; Franke Visiting Fellow, Whitney Humanities Center, Yale; author, 36 Arguments for the Existence of God: A Work of Fiction

  This year’s Edge Question sits uneasily on a deeper question: Where do we get the idea—a fantastic idea, if you stop and think about it—that the beauty of an explanation has anything to do with the likelihood of its being true? What do beauty and truth have to do with each other? Is there any good explanation of why the central notion of aesthetics (fluffy) should be inserted into the central notion of science (rigorous)?

  You might think that rather than being a criterion for assessing explanations, the sense of beauty is a phenomenon to be explained away. Take, for example, our impression that symmetrical faces and bodies are beautiful. Symmetry, it turns out, is a good indicator of health and consequently of mate-worthiness. It’s a significant challenge for an organism to coordinate the production of its billions of cells so that its two sides proceed to develop as perfect matches, warding off disease and escaping injury, mutation, and malnutrition. Symmetrical female breasts, for example, are a good predictor of fertility. As our lustful genes know, the achievement of symmetry is a sign of genetic robustness; we find lopsidedness a turnoff. So, too, in regard to other components of human beauty—radiant skin, shining eyes, neotony (at least in women). The upshot is that we don’t want to mate with people because they’re beautiful; rather, they’re beautiful because we want to mate with them, and we want to mate with them because our genes are betting on them as replicators.

  So, too, you might think that beauty of every sort is to be similarly explained away, an attention-grabbing epiphenomenon with no substance of its own. Which brings me to the Edge Question concerning beautiful explanations. Is there anything to this notion of explanatory beauty, a guide to choosing between explanatory alternatives, or is it just that any explanation that’s satisfactory will, for that very reason and no other, strike us as beautiful, beautifully explanatory, so that the reference to beauty is, once again, without any substance? That would be an explanation for the mysterious injection of aesthetics into science. The upshot would be that explanations aren’t satisfying because they’re beautiful; rather, they’re beautiful because they’re satisfying. They strip the phenomenon bare of all mystery and maybe, as a bonus, pull in further phenomena which can be rendered nonmysterious using the same sort of explanation. Can explanatory beauty be explained away, summarily dismissed by way of an eliminative explanation? (Eliminative explanations are beautiful.)

  I’d like to stop here, with a beautiful explanation for explaining away explanatory beauty, but somebody is whispering in my ear. It’s that damned Plato. Plato is going on about how there is more in the idea of explanatory beauty than is acknowledged in the eliminative explanation. In particular, he’s insisting, as he does in his Timaeus, that the beauty of symmetry, especially as it’s expressed in the mathematics of physical laws, cannot be explained away with the legerdemain of the preceding paragraph. He’s reproaching the eliminative explanation of explanatory beauty with ignoring the many examples in history when the insistence on the beauty of symmetry led to substantive scientific progress. What was it that led James Clerk Maxwell to his four equations of electromagnetism but his trying to impose mathematical symmetry on the domains of electricity and magn
etism? What was it that led Einstein to his equations of gravity but an insistence on beautiful mathematics?

  Eliminative explanations are beautiful, but only when they truly and thoroughly explain. So instead of offering an answer to this year’s Edge Question, I offer instead an unresolved (and, therefore, unbeautiful) reaction to the deep question on which it rests.

  PTOLEMY’S UNIVERSE

  JAMES J. O’DONNELL

  Classicist; provost, Georgetown University; author, The Ruin of the Roman Empire

  Claudius Ptolemy explained the sky. He was an Egyptian who wrote in Greek in the Roman Empire, in the time of emperors like Trajan and Hadrian. His most famous book was called by its Arabic translators the Almagest. He inherited a long ancient tradition of astronomical science going back to Mesopotamia, but he put his name and imprint on the most successful and so far longest-lived mathematical description of the working of the skies.

  Ptolemy’s geocentric universe is now known mainly as the thing that was rightly abandoned by Copernicus, Kepler, Newton, and Einstein, in progressive waves of the advancement of modern science, but he deserves our deep admiration. Ptolemy’s universe actually made sense. He knew the difference between planets and stars and he knew that the planets take some explaining. (The Greek word planet means “wanderer,” to reflect ancient puzzlement that those bright lights moved according to no pattern that a shepherd or seaman could intuitively predict, unlikely the reassuringly confident annual march of Orion or the rotation of the great bears overhead.) So Ptolemy represents the heavenly machine in a complex mathematical system most notorious for its “epicycles”—the orbits within orbits, so to speak, by which the planets, while orbiting the Earth, spun off their orbits in smaller circles that explained their seeming forward and backward motion in the night sky.