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Authors: Shimon Edelman
The Happiness of Pursuit: What Neuroscience Can Teach Us About the Good Life (7 page)
BOOK: The Happiness of Pursuit: What Neuroscience Can Teach Us About the Good Life
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For the stealthy slippers scenario, the “why?” question has long been settled by the person in whose mind it originated: Philip K. Dick, the prophetic purveyor of philosophical paranoia, which he dressed up as science fiction and sold to pulp publishers to make a living. In the story “The Short Happy Life of a Brown Oxford,” one of Dick’s cartoonish scientist characters introduces a “Principle of Sufficient Irritation,” according to which inanimate objects, such as shoes, can only take so much abuse before they try to do something about it.
2
Before the shoe’s bewildered owner could take up the “how?” question, the newly animate runaway shoe in the story got away in pursuit of a lady shoe love interest, proving the effectiveness of the
cherchez la femme
cliché in settling the “why?” question in the male-dominated genre that was 1950s sci-fi.
2
Before the shoe’s bewildered owner could take up the “how?” question, the newly animate runaway shoe in the story got away in pursuit of a lady shoe love interest, proving the effectiveness of the
cherchez la femme
cliché in settling the “why?” question in the male-dominated genre that was 1950s sci-fi.
The truth, however, is often stranger than even PKD’s fiction. Earth’s biosphere is replete with microscopic clumps of organized matter—single cells, such as bacteria or brewer’s yeast, which we tend to regard as hardly more animate than a shoe—that sense, process, and act on outside chemical information, in the service of higher purposes with which shoe-wearing multicellular hulks can readily identify. One such purpose is sustenance:
E. coli
bacteria, for example, can sense minute directional differences in the concentration of useful metabolites such as aspartate and swim in the direction of the higher concentration. Another purpose is procreation: yeast cells sense and follow pheromone gradients that lead to receptive members of the opposite sex.
E. coli
bacteria, for example, can sense minute directional differences in the concentration of useful metabolites such as aspartate and swim in the direction of the higher concentration. Another purpose is procreation: yeast cells sense and follow pheromone gradients that lead to receptive members of the opposite sex.
The investigation, then, begins with the big “why” and continues with a series of “whats” and “hows.”
Why
did a yeast cell cross the road? To get to the block party.
How
could it tell which way the party was? By sensing where the pheromones were drifting from.
What
did it need to compute to find that out? The concentration of pheromones in each direction—the direction in which it was higher points to the source. But if pheromone molecules hit the cell and bounce off it,
how
could it avoid counting the same molecule more than once and getting the direction of the higher concentration wrong? By capturing molecules that hit its specialized pheromone receptors and metabolizing them into some other stuff. (This is the cell’s equivalent of counting items off on its fingers and setting them aside.)
3
And
how
did it get closer to its prospective mate? By growing a projection, known as a shmoo (I am not kidding), in the right direction.
Why
did a yeast cell cross the road? To get to the block party.
How
could it tell which way the party was? By sensing where the pheromones were drifting from.
What
did it need to compute to find that out? The concentration of pheromones in each direction—the direction in which it was higher points to the source. But if pheromone molecules hit the cell and bounce off it,
how
could it avoid counting the same molecule more than once and getting the direction of the higher concentration wrong? By capturing molecules that hit its specialized pheromone receptors and metabolizing them into some other stuff. (This is the cell’s equivalent of counting items off on its fingers and setting them aside.)
3
And
how
did it get closer to its prospective mate? By growing a projection, known as a shmoo (I am not kidding), in the right direction.
Even with unicellular life, there seems to be no end in sight to the march of questions. Entire scientific careers can be (and increasingly are) spent on understanding exclusively some genetic, metabolic, signaling, or structural aspect of life’s minutiae, such as growing shmoos in yeast. Interestingly, however, the very same questions apply, level by level, to all purposive information processors, from a single-cell replicator, propelled by a simple mind to seek a mate, to a considerably more complex replicator whose mind, with tragic foresight, “misgives some consequence yet hanging in the stars” and whose pursuit of happiness is soon checked by fortune’s hand:
BENVOLIOHere comes the furious Tybalt back again.ROMEOAlive, in triumph! and Mercutio slain!
Away to heaven, respective lenity,
And fire-eyed fury be my conduct now!Re-enter
TYBALT.Now, Tybalt, take the villain back again,
That late thou gavest me; for Mercutio’s soul
Is but a little way above our heads,
Staying for thine to keep him company:
Either thou, or I, or both, must go with him.TYBALTThou, wretched boy, that didst consort him here,
Shalt with him hence.ROMEOThis shall determine that.They fight;
TYBALT
falls.BENVOLIORomeo, away, be gone!
The citizens are up, and Tybalt slain.
Stand not amazed: the prince will doom thee death,
If thou art taken: hence, be gone, away!ROMEOO, I am fortune’s fool!BENVOLIO
Why does Romeo linger at the scene of the sword fight, and why does he eventually leave it? Shakespeare engages us not because his protagonists’ motives, decisions, and actions are unfathomable. On the contrary, intuitively we probably know the answers to many of the questions that apply. We should therefore be glad to have come into possession of a conceptual tool kit that is honed so as to dispel whatever mysteries still cling to human nature—those attached to the as-yet-unanswered “why?” and “how?” questions.
Let us arrange our tools on the bench, then. The no. 1 tool is the conceptual lens through which we can see everything as computation. The no. 2 tool is an assay for mindfulness, which helps us separate boring computing for its own sake (falling pebbles or flung penguins) from interesting representational computing (sensing, signaling, and behavior-inducing neurons, cogs, or transistors). The no. 3 tool is a zoom attachment that allows us to focus on various levels of explanation—from the more general “why” questions, whose likely answers will be couched in complex terms that in turn require further explanation (as in “Romeo killed Tybalt in revenge for the death of his kinsman Mercutio”), to the more specific questions about the “how” and the “what” of the corresponding computations (like those carried out by the neuropharmacological circuits that embody what Romeo proclaims to be his “fire-eyed fury” and that are too numerous to list here).
5
5
By making use of these tools, we will be able to recognize the
problems
that all minds, natural or artificial, must contend with; to see which
tactics
may help solve the problems; and to convince ourselves that
implementations
of the tactics are possible that rely only on the available means and materials. Some of the necessary work we already did in the previous chapter, when it was made clear that the world is sufficiently well behaved, statistically speaking, to make attempted forethought pay for itself. This is where we should pick up the thread, then, starting with forethought and zooming in and out through the issues as they arise, wherever the quest takes us.
Faster Than a Speeding Marmotproblems
that all minds, natural or artificial, must contend with; to see which
tactics
may help solve the problems; and to convince ourselves that
implementations
of the tactics are possible that rely only on the available means and materials. Some of the necessary work we already did in the previous chapter, when it was made clear that the world is sufficiently well behaved, statistically speaking, to make attempted forethought pay for itself. This is where we should pick up the thread, then, starting with forethought and zooming in and out through the issues as they arise, wherever the quest takes us.
Seeing that forethought is possible in the world we inhabit, how does it actually work? All of us information-processing creatures, from yeast to the citizens of Verona, practice forethought, but the details of how we go about it vary widely.
A lot depends on where you live and who your neighbors are. In many corners of this planet’s biosphere, following literally the model of blind Molly from the last chapter (that is, banging your head on the ceiling and digging through dirt in the direction that seems most auspicious, given the echo) would be detrimental to your chances of seeing your kids through college, or at least seeing them have kids of their own—the point at which evolution finally seems to relent from its personal interest in you and you are free to enjoy retirement, if you can afford it.
Because in evolution there is no top of the heap in an absolute sense, it is equally meaningless to claim that the Duke of Verona is either more or less successful than the yeast that froths his beer. It does, however, make sense to ask what general behavioral recipes and abilities are shared by all naturally occurring forethought-practicing entities (and of course what computations are needed to support such abilities). There is little integrative work on this question in cognitive science (neuroethologists and neurobiologists tend to study particular behaviors or subsystems in certain species, and roboticists too shun generalities, all for very understandable reasons),
6
and so common sense will have to do.
6
and so common sense will have to do.
Take, for example, this superpower that I possess: dodging marmots. It may not sound like much, but unlike the superpowers of comic-book heroes and some misguided citizens,
7
mine is real, as I was able to verify a few years ago during a hike in Mt. Rainier National Park, which is near Seattle. A self-propelled marmot is very easy for a primate like me to dodge. I can sense its approach while it is still at a safe distance, even if it is trying to sneak up on me; I do it by intercepting and measuring the ambient light that is reflected from it and process the images to recognize it as a marmot and to estimate its distance, heading, and speed. I can use my intuitive knowledge of physics (distilled from years of experience going to and fro on the earth and walking up and down on it) to extrapolate the marmot’s trajectory and to decide whether or not I need to act. If I do, I send a series of signals to my muscles that bring about the intended end result, which is a frustrated marmot. Voilà!
7
mine is real, as I was able to verify a few years ago during a hike in Mt. Rainier National Park, which is near Seattle. A self-propelled marmot is very easy for a primate like me to dodge. I can sense its approach while it is still at a safe distance, even if it is trying to sneak up on me; I do it by intercepting and measuring the ambient light that is reflected from it and process the images to recognize it as a marmot and to estimate its distance, heading, and speed. I can use my intuitive knowledge of physics (distilled from years of experience going to and fro on the earth and walking up and down on it) to extrapolate the marmot’s trajectory and to decide whether or not I need to act. If I do, I send a series of signals to my muscles that bring about the intended end result, which is a frustrated marmot. Voilà!
It would be a more serious matter if marmots were ever used against me as missiles by an ill-wisher. If it was hurled by hand or dropped from a balcony, I might still be able to see the incoming marmot in time to step aside, at least if I acted sharp, whereas a drone-launched marmot could easily prove lethal. The worst scenario, however, would be one in which I, for whatever reason, no longer cared. A depressed person, who lacks the basic motivation to act, even in self-defense, is quite easy to hit with a marmot.
This last observation explains why the general recipe for managing behavior through forethought must begin with the need to get off one’s behind.
8
Once you do, you can sense things before they happen to you, plot a course of action based on the sensed data and on past experience, and execute the chosen maneuvers. The ingredients of this recipe are familiar to every psychology student under their textbook labels: motivation, perception, thinking, and motor control.
9
They are easiest to understand when taken up in a somewhat different order. It begins with perception, a clear view of which is critical for grasping both how possibilities for action present themselves to minds and what motivation means computationally. Because thinking is where the main potential for complexity and sophistication in cognition is found, most of the thinking about thinking will be postponed until later in the book.
A Treatise of Human Nature8
Once you do, you can sense things before they happen to you, plot a course of action based on the sensed data and on past experience, and execute the chosen maneuvers. The ingredients of this recipe are familiar to every psychology student under their textbook labels: motivation, perception, thinking, and motor control.
9
They are easiest to understand when taken up in a somewhat different order. It begins with perception, a clear view of which is critical for grasping both how possibilities for action present themselves to minds and what motivation means computationally. Because thinking is where the main potential for complexity and sophistication in cognition is found, most of the thinking about thinking will be postponed until later in the book.
Even if it seems natural to conceive of perception as a window through which the brain, in the safe house of the skull, monitors the neighborhood for any developments or portents, this conception is wrong. Suppose that an embrained but as yet sightless mind, desperately in need of distraction from its confinement, decides to watch a football game. Sawing through the front of its body’s face to make a window to let the light shine on the brain would be as futile in trying to get it to see as installing a little TV screen on the inside and connecting it to a camera looking out. To see things through such a window or on the internal screen, the brain would need something like an eye, along with the machinery that processes what the eye tells it. This, of course, is exactly what a regular human brain already has, which demonstrates that the window/TV simile merely postpones the explanation instead of providing one.
The path to a real explanation begins with the realization that vision and other senses deliver variously
interpreted
representations of the world rather than snapshots or recordings of it. Thus, it is more useful to think of the process of seeing a football game play out not as a video transmission for the benefit of an internal viewer, but rather as a radio show in which a boxful of commentators, speaking all at once, describe the action to a bunch of listeners.
interpreted
representations of the world rather than snapshots or recordings of it. Thus, it is more useful to think of the process of seeing a football game play out not as a video transmission for the benefit of an internal viewer, but rather as a radio show in which a boxful of commentators, speaking all at once, describe the action to a bunch of listeners.
Why multiple “commentators”? Because an analogy with a single running commentary would only ever suffice to explain a very, very simple perceiver, such as perhaps a household thermostat, whose comments on any action in the house would go like this: “ . . . ; too cold; too cold; just right; just right; just right; too warm; just right. . . . ” A slightly fancier thermostat that also includes a temperature display provides two related but not identical commentaries on the same situation: one is the on/off track, delivered exclusively for the benefit of the air conditioner, and the other is the number in the little window that shows the temperature. An even better one could include a humidity reading, which perhaps could be wired to a humidity control device that is separate from the air-conditioning unit.
The possibility of a perceptual information stream having more than one destination explains why in drawing an analogy between perception and a radio show I made a point of including not just multiple “commentators” but also multiple “listeners.” At the very least, the household climate control system just described must have
two
distinct “listeners” that use the information provided by the sensing channels (the hygrometer and the thermometer): one in charge of the humidifier and the other in charge of the air conditioning. So, if anyone attempts to sell you the idea of a single, indivisible black box labeled THINKING as an explanation for how perceptions give rise to actions, expose it as sham by asking, “Yes, but what’s going on inside the box?”
two
distinct “listeners” that use the information provided by the sensing channels (the hygrometer and the thermometer): one in charge of the humidifier and the other in charge of the air conditioning. So, if anyone attempts to sell you the idea of a single, indivisible black box labeled THINKING as an explanation for how perceptions give rise to actions, expose it as sham by asking, “Yes, but what’s going on inside the box?”
BOOK: The Happiness of Pursuit: What Neuroscience Can Teach Us About the Good Life
12.05Mb size Format: txt, pdf, ePub
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