Indeed, let us think for a moment about such a gas — a gas in a cylinder with a movable piston. If the gas suddenly heats up (as occurs in any cylinder in your car engine when its spark plug fires), then its pressure suddenly increases and therefore (note the causal word) the piston is suddenly shoved outwards. Thus combustion engines can be built.
What I just told is the story at a gross (thermodynamic) level. Nobody who designs combustion engines worries about the fine-grained level — that of molecules. No engineer tries to figure out the exact trajectories of 1023 molecules banging into each other! The locations and velocities of individual molecules are simply irrelevant. All that matters is that they can be counted on to collectively push the piston out. Indeed, it doesn’t matter whether they are molecules of type X or type Y or type Z — pressure is pressure, and that’s all that matters. The explosion — a high-level event — will do its job in heating the gas, and the gas will do its job in pushing the piston. This high-level description of what happens is the only level of description that is relevant, because all the microdetails could be changed and exactly the same thing (at least from the human engineer’s point of view) would still happen.
The Strange Irrelevance of Lower Levels
This idea — that the bottom level, though 100 percent responsible for what is happening, is nonetheless irrelevant to what happens — sounds almost paradoxical, and yet it is an everyday truism. Since I want this to be crystal-clear, let me illustrate it with one more example.
Consider the day when, at age eight, I first heard the fourth étude of Chopin’s Opus 25 on my parents’ record player, and instantly fell in love with it. Now suppose that my mother had placed the needle in the groove a millisecond later. One thing for sure is that all the molecules in the room would have moved completely differently. If you had been one of those molecules, you would have had a wildly different life story. Thanks to that millisecond delay, you would have careened and bashed into completely different molecules in utterly different places, spun off in totally different directions, and on and on, ad infinitum. No matter which molecule you were in the room, your life story would have turned out unimaginably different. But would any of that have made an iota of difference to the life story of the kid listening to the music? No — not the teensiest, tiniest iota of difference. All that would have mattered was that Opus 25, number 4 got transmitted faithfully through the air, and that would most surely have happened. My life story would not have been changed in any way, shape, or form if my mother had put the needle down in the groove a millisecond earlier or later. Or a second earlier or later.
Although the air molecules were crucial mediating agents for a series of high-level events involving a certain kid and a certain piece of music, their precise behavior was not crucial. Indeed, saying it was “not crucial” is a ridiculous understatement. Those air molecules could have done exactly the same kid–music job in an astronomical number of different but humanly indistinguishable fashions. The lower-level laws of their collisions played a role only in that they gave rise to predictable high-level events (propagation of the notes in the Chopin étude to little Douggie’s ear). But the positions, speeds, directions, even the chemical identity of the molecules — all of this was changeable, and the high-level events would have been the same. It would have been the same music to my ears. One can even imagine that the microscopic laws of physics could have been different — what matters is not the detailed laws but merely the fact that they reliably give rise to stable statistical consequences.
Flip a quarter a million times and you’ll very reliably get within one percent of 500,000 heads. Flip a penny the same number of times, and the same statement holds. Use a different coin on every flip — dimes, quarters, new pennies, old pennies, buffalo nickels, silver dollars, you name it — and still you’ll get the same result. Shave your penny so that its outline is hexagonal instead of circular — no difference. Replace the hexagonal outline by an elephant shape. Dip the penny in apple butter before each flip. Bat the penny high into the air with a baseball bat instead of tossing it up. Flip the penny in helium gas instead of air. Do the experiment on Mars instead of Earth. These and countless other variations on the theme will not have any effect on the fact that out of a million tosses, within one percent of 500,000 will wind up heads. That high-level statistical outcome is robust and invariant against the details of the substrate and the microscopic laws governing the flips and bounces; the high-level outcome is insulated and sealed off from the microscopic level. It is a fact in its own right, at its own level.
That is what it means to say that although what happens on the lower level is responsible for what happens on the higher level, it is nonetheless irrelevant to the higher level. The higher level can blithely ignore the processes on the lower level. As I put it in Chapter 2, “Our existence as animals whose perception is limited to the world of everyday macroscopic objects forces us, quite obviously, to function without any reference to entities and processes at microscopic levels. No one really knew the slightest thing about atoms until only about a hundred years ago, and yet people got along perfectly well.”
A Hat-tip to the Spectrum of Unpredictability
I am not suggesting that the invisible, swarming, chaotic, microscopic level of the world can be totally swept under the rug and forgotten. Although in many circumstances we rely on the familiar macroworld to be completely predictable to us, there are many other circumstances where we are very aware of not being able to predict what will happen. Let me first, however, make a little list of some sample predictables that we rely on unthinkingly all the time.
When we turn our car’s steering wheel, we know for sure where our car will go; we don’t worry that a band of recalcitrant little molecules might mutiny and sabotage our turn. When we turn a burner to “high” under a saucepan filled with water, we know that the water will boil within a few minutes. We can’t predict the pattern of bubbles inside the boiling water, but we really don’t give a hoot about that. When we take a soup can down from the shelf in the grocery store and place it in our cart, we know for sure that it will not turn into a bag of potato chips, will not burn our hand, will not be so heavy that we cannot lift it, will not slip through the grill of the cart, will sit still if placed vertically, and so forth. To be sure, if we lay the soup can down horizontally and start wheeling the cart around the store, the can will roll about in the cart in ways that are not predictable to us, though they lie completely within the bounds of our expectations and have little interest or import to us, aside from being mildly annoying.
When we speak words, we know that they will reach the ears of our listeners without being changed by the intermediary pressure waves into other words, will even come through with the exact intonations that we impart to them. When we pour milk into a glass, we know just how far to tilt the milk container to get the desired amount of flow without spilling a drop. We control the milk and we get exactly the result we want.
There is no surprise in any of this! And I could extend this list forever, and it would soon grow very boring, because you know it all instinctively and take it totally for granted. Every day of our lives, we all depend in a million tacit ways on innumerable rock-solid predictabilities about how things happen in the visible, tangible world (the solidity of rocks being yet another of those countless rock-solid predictabilities).
On the other hand, there’s also plenty of unpredictability “up here” in the macroworld. How about a second list, giving typical unpredictables?
When we toss a basketball towards a basket, we don’t have any idea whether it will go through or not. It might bounce off the backboard and then teeter for a couple of seconds on the rim, keeping us in suspense and perhaps even holding an entire crowd in tremendous, tingling tension. A championship basketball game could go one way or the other, depending on a microscopic difference in the position of the pinky of the player who makes a desperate last-second shot.
When we begin to utter a thought,
we have no idea what words we will wind up using nor which grammatical pathways we will wind up following, nor can we predict the speech errors or the facts about our unconscious mind that our little slips will reveal. Usually such revelations will make little difference, but once in a while — in a job interview, say — they can have huge repercussions. Think of how people jump on a politician whose unconscious mind chooses a word loaded with political undertones (e.g., “the crusade against terrorism”).
When we ski down a slope, we don’t know if we’re going to fall on our next turn or not. Every turn is a risk — slight for some, large for others. A broken bone can come from an event whose cause we will never fathom, because it is so deeply hidden in detailed interactions between the snow and our ski. And the tiniest detail about the manner in which we fall can make all the difference as to whether we suffer a life-changing multiple break or a just a trivial hairline fracture.
The macroscopic world as experienced by humans is, in short, an intimate mixture ranging from the most predictable events all the way to wildly unpredictable ones. Our first few years of life familiarize us with this spectrum, and the degree of predictability of most types of actions that we undertake becomes second nature to us. By the time we emerge from childhood, we have acquired a reflex-level intuition for where most of our everyday world’s loci of unpredictability lie, and the more unpredictable end of this spectrum simultaneously beckons to us and frightens us. We’re pulled by but fearful of risk-taking. That is the nature of life.
The Careenium
I now move to a somewhat more complex metaphor for thinking about the multiple levels of causality in our brains and minds (and eventually, if you will indulge me in this terminology, in our souls). Imagine an elaborate frictionless pool table with not just sixteen balls on it, but myriads of extremely tiny marbles, called “sims” (an acronym for “small interacting marbles”). These sims bash into each other and also bounce off the walls, careening about rather wildly in their perfectly flat world — and since it is frictionless, they just keep on careening and careening, never stopping.
So far our setup sounds like a two-dimensional ideal gas, but now we’ll posit a little extra complexity. The sims are also magnetic (so let’s switch to “simms”, with the extra “m” for “magnetic”), and when they hit each other at lowish velocities, they can stick together to form clusters, which I hope you will pardon me for calling “simmballs”. A simmball consists of a very large number of simms (a thousand, a million, I don’t care), and on its periphery it frequently loses a few simms while gaining others. There are thus two extremely different types of denizen of this system: tiny, light, zipping simms, and giant, ponderous, nearly-immobile simmballs.
The dynamics taking place on this pool table — hereinafter called the “careenium” — thus involves simms crashing into each other and also into simmballs. To be sure, the details of the physics involve transfers of momentum, angular momentum, kinetic energy, and rotational energy, just as in a standard gas, but we won’t even think about that, because this is just a thought experiment (in two senses of the term). All that matters for our purposes is that there are these collisions taking place all the time.
Simmballism
Why the corny pun on “symbol”? Because I now add a little more complexity to our system. The vertical walls that constitute the system’s boundaries react sensitively to outside events (e.g., someone touching the outside of the table, or even a breeze) by momentarily flexing inward a bit. This flexing, whose nature retains some traces of the external causing event, of course affects the motions of the simms that bounce internally off that section of wall, and indirectly this will be registered in the slow motions of the nearest simmballs as well, thus allowing the simmballs to internalize the event. We can posit that one particular simmball always reacts in some standard fashion to breezes, another to sharp blows, and so forth. Without going into details, we can even posit that the configurations of simmballs reflect the history of the impinging outer-world events. In short, for someone who looked at the simmballs and knew how to read their configuration, the simmballs would be symbolic, in the sense of encoding events. That’s why the corny pun.
Of course this image is far-fetched, but remember that the careenium is merely intended as a useful metaphor for understanding our brains, and the fact is that our brains, too, are rather far-fetched, in the sense that they too contain tiny events (neuron firings) and larger events (patterns of neuron firings), and the latter presumably somehow have representational qualities, allowing us to register and also to remember things that happen outside of our crania. Such internalization of the outer world in symbolic patterns in a brain is a pretty far-fetched idea, when you think about it, and yet we know it somehow came to exist, thanks to the pressures of evolution. If you wish, then, feel free to imagine that careenia, too, evolved. You can think of them as emerging as the end result of billions of more primitive systems fighting for survival in the world. But the evolutionary origins of our careenium need not concern us here. The key idea is that whereas no simm on its own encodes anything or plays a symbolic role, the simmballs, on their far more macroscopic level, do encode and are symbolic.
Taking the Reductionistic View of the Careenium
The first inclination of a modern physicist who heard this story might be reductionistic, in the sense of pooh-poohing the large simmballs as mere epiphenomena, meaning that although they are undeniably there, they are not essential to an understanding of the system, since they are composed of simms. Everything that happens in the careenium is explainable in terms of simms alone. And there’s no doubt that this is true. A volcano, too, is undeniably there, but who needs to talk about mountains and subterranean pressures and eruptions and lava and such things? We can dispense with such epiphenomenal concepts altogether by shifting to the deeper level of atoms or elementary particles. The bottom line, at least for our physicist, is that epiphenomena are just convenient shorthands that summarize a large number of deeper, lower-level phenomena; they are never essential to any explanation. Reductionism ho!
The only problem is the enormous escalation in complexity when we drop all macroscopic terms and ways of looking at things. If we refuse to use any language that involves epiphenomena, then we are condemned to seeing only untold myriads of particles, and that is certainly not a very welcoming thought. Moreover, when one perceives only myriads of particles, there are no natural sharp borders in the world. One cannot draw a line around the volcano and declare, “Only particles in this zone are involved”, because particles won’t respect any such macroscopic line — no more than ants respect the property lines carefully surveyed and precisely drawn by human beings. No fixed portion of the universe can be tightly fenced off from interacting with the rest — not even approximately. To a reductionist, the idea of carving the universe up into zones with inviolable macroscopic spatiotemporal boundary lines makes no sense.
Here is a striking example of the senselessness of local spatiotemporal boundaries. In November of 1993, I read several newspaper articles about a comet that was “slowly” making its way towards Jupiter. It was still some eight months from t-zero but astrophysicists had already predicted to the minute, if not to the second, when it would strike Jupiter, and where. This fact about some invisible comet that was billions of miles away from earth had already had enormous impacts on the surface of our planet, where teams of scientists were already calculating its Jovian arrival time, where newspapers and magazines were already printing front-page stories about it, and where millions of people like me were already reading about it. Some of these people were possibly missing planes because of being engrossed in the story, or possibly striking up a new friendship with someone because of a common interest in it, or possibly arriving at a traffic light one second later than otherwise because of having reread one phrase in the article, and so on. As t-zero approached and finally the comet hit Jupiter’s far side exactly as predicted, denizens of the Earth paid enormous att
ention to this remote cosmic event. There is no doubt that many months before the comet hit Jupiter, certain fender-benders took place on our planet that wouldn’t have taken place if the comet hadn’t been coming, certain babies were conceived that wouldn’t have been conceived otherwise, certain flies were swatted, certain coffee cups were chipped, and so on. All of this crazy stuff happening on our tiny planet was due to a comet coasting through silent space billions of miles away and nearly half a million minutes in advance of its encounter with the huge planet.
The point is that one gets into very hot water if one goes the fully reductionistic route; not only do all the objects in “the system” become microscopic and uncountably numerous, but also the system itself grows beyond bounds in space and time and becomes, in the end, the entire universe taken over all of time. There is no comprehensibility left, since everything is shattered into a trillion trillion trillion invisible pieces that are scattered hither and yon. Reductionism is merciless.
Taking a Higher-level View of the Careenium
If, on the other hand, there is a perceptible and comprehensible “logic” to events at the level of epiphenomena, then we humans are eager to jump to that level. In fact, we have no choice. And so we do talk of volcanoes and eruptions and lava and so forth. Likewise, we talk of bitten fingernails and rye bread and wry smiles and Jewish senses of humor rather than of cells and proteins, let alone of atoms and photons. After all, we ourselves are pretty big epiphenomena, and as I’ve already observed many times in this book, this fact dooms us to talking about the world in terms of other epiphenomena at about our size level (e.g., our mothers and fathers, our cats and cars and cakes, our sailboats and saxophones and sassafras trees).
I Am a Strange Loop Page 8
