Followup to:  The Generalized Anti-Zombie Principle

One generalized lesson not to learn from the Anti-Zombie Argument is, "Anything you can't see doesn't exist."

It's tempting to conclude the general rule.  It would make the Anti-Zombie Argument much simpler, on future occasions, if we could take this as a premise.  But unfortunately that's just not Bayesian.

Suppose I transmit a photon out toward infinity, not aimed at any stars, or any galaxies, pointing it toward one of the great voids between superclusters.  Based on standard physics, in other words, I don't expect this photon to intercept anything on its way out.  The photon is moving at light speed, so I can't chase after it and capture it again.

If the expansion of the universe is accelerating, as current cosmology holds, there will come a future point where I don't expect to be able to interact with the photon even in principle—a future time beyond which I don't expect the photon's future light cone to intercept my world-line.  Even if an alien species captured the photon and rushed back to tell us, they couldn't travel fast enough to make up for the accelerating expansion of the universe.

Should I believe that, in the moment where I can no longer interact with it even in principle, the photon disappears?

No.

It would violate Conservation of Energy.  And the second law of thermodynamics.  And just about every other law of physics.  And probably the Three Laws of Robotics.  It would imply the photon knows I care about it and knows exactly when to disappear.

It's a silly idea.

But if you can believe in the continued existence of photons that have become experimentally undetectable to you, why doesn't this imply a general license to believe in the invisible?

(If you want to think about this question on your own, do so before the jump...)

Followup to:  The Generalized Anti-Zombie Principle

In "The Unimagined Preposterousness of Zombies", Daniel Dennett says:

To date, several philosophers have told me that they plan to accept my challenge to offer a non-question-begging defense of zombies, but the only one I have seen so far involves postulating a "logically possible" but fantastic being — a descendent of Ned Block's Giant Lookup Table fantasy...

A Giant Lookup Table, in programmer's parlance, is when you implement a function as a giant table of inputs and outputs, usually to save on runtime computation.  If my program needs to know the multiplicative product of two inputs between 1 and 100, I can write a multiplication algorithm that computes each time the function is called, or I can precompute a Giant Lookup Table with 10,000 entries and two indices.  There are times when you do want to do this, though not for multiplication—times when you're going to reuse the function a lot and it doesn't have many possible inputs; or when clock cycles are cheap while you're initializing, but very expensive while executing.

Giant Lookup Tables get very large, very fast.  A GLUT of all possible twenty-ply conversations with ten words per remark, using only 850-word Basic English, would require 7.6 * 10⁵⁸⁵ entries.

Replacing a human brain with a Giant Lookup Table of all possible sense inputs and motor outputs (relative to some fine-grained digitization scheme) would require an unreasonably large amount of memory storage.  But "in principle", as philosophers are fond of saying, it could be done.

Continuation of:  Zombies! Zombies?

I'm a bit tired today, having stayed up until 3AM writing yesterday's >6000-word post on zombies, so today I'll just reply to Richard, and tie up a loose end I spotted the next day.

Besides, TypePad's nitwit, un-opt-out-able 50-comment pagination "feature", that doesn't work with the Recent Comments sidebar, means that we might as well jump the discussion here before we go over the 50-comment limit.

Your "zombie", in the philosophical usage of the term, is putatively a being that is exactly like you in every respect—identical behavior, identical speech, identical brain; every atom and quark in exactly the same position, moving according to the same causal laws of motion—except that your zombie is not conscious.

It is furthermore claimed that if zombies are "possible" (a term over which battles are still being fought), then, purely from our knowledge of this "possibility", we can deduce a priori that consciousness is extra-physical, in a sense to be described below; the standard term for this position is "epiphenomenalism".

(For those unfamiliar with zombies, I emphasize that this is not a strawman.  See, for example, the SEP entry on Zombies.  The "possibility" of zombies is accepted by a substantial fraction, possibly a majority, of academic philosophers of consciousness.)

I once read somewhere, "You are not the one who speaks your thoughts—you are the one who hears your thoughts".  In Hebrew, the word for the highest soul, that which God breathed into Adam, is N'Shama—"the hearer".

If you conceive of "consciousness" as a purely passive listening, then the notion of a zombie initially seems easy to imagine.  It's someone who lacks the N'Shama, the hearer.

(Warning:  Long post ahead.  Very long 6,600-word post involving David Chalmers ahead.  This may be taken as my demonstrative counterexample to Richard Chappell's Arguing with Eliezer Part II, in which Richard accuses me of not engaging with the complex arguments of real philosophers.)

Followup to:  Reductionism, Explaining vs. Explaining Away, Hand vs. Fingers, Heat vs. Motion

The reductionist thesis (as I formulate it) is that human minds, for reasons of efficiency, use a multi-level map in which we separately think about things like "atoms" and "quarks", "hands" and "fingers", or "heat" and "kinetic energy".  Reality itself, on the other hand, is single-level in the sense that it does not seem to contain atoms as separate, additional, causally efficacious entities over and above quarks.

Sadi Carnot formulated the (precursor to) the second law of thermodynamics using the caloric theory of heat, in which heat was just a fluid that flowed from hot things to cold things, produced by fire, making gases expand—the effects of heat were studied separately from the science of kinetics, considerably before the reduction took place.  If you're trying to design a steam engine, the effects of all those tiny vibrations and collisions which we name "heat" can be summarized into a much simpler description than the full quantum mechanics of the quarks.  Humans compute efficiently, thinking of only significant effects on goal-relevant quantities.

But reality itself does seem to use the full quantum mechanics of the quarks.  I once met a fellow who thought that if you used General Relativity to compute a low-velocity problem, like an artillery shell, GR would give you the wrong answer—not just a slow answer, but an experimentally wrong answer—because at low velocities, artillery shells are governed by Newtonian mechanics, not GR.  This is exactly how physics does not work.  Reality just seems to go on crunching through General Relativity, even when it only makes a difference at the fourteenth decimal place, which a human would regard as a huge waste of computing power.  Physics does it with brute force.  No one has ever caught physics simplifying its calculations—or if someone did catch it, the Matrix Lords erased the memory afterward.

Our map, then, is very much unlike the territory; our maps are multi-level, the territory is single-level.  Since the representation is so incredibly unlike the referent, in what sense can a belief like "I am wearing socks" be called true, when in reality itself, there are only quarks?

In an amazing breakthrough, a multinational team of scientists led by Nobel laureate Santiago Ramón y Cajal announced that the brain is composed of a ridiculously complicated network of tiny cells connected to each other by infinitesimal threads and branches.

The multinational team—which also includes the famous technician Antonie van Leeuwenhoek, and possibly Imhotep, promoted to the Egyptian god of medicine—issued this statement:

"The present discovery culminates years of research indicating that the convoluted squishy thing inside our skulls is even more complicated than it looks.  Thanks to Cajal's application of a new staining technique invented by Camillo Golgi, we have learned that this structure is not a continuous network like the blood vessels of the body, but is actually composed of many tiny cells, or "neurons", connected to one another by even more tiny filaments.

"Other extensive evidence, beginning from Greek medical researcher Alcmaeon and continuing through Paul Broca's research on speech deficits, indicates that the brain is the seat of reason.

"Nemesius, the Bishop of Emesia, has previously argued that brain tissue is too earthy to act as an intermediary between the body and soul, and so the mental faculties are located in the ventricles of the brain.  However, if this is correct, there is no reason why this organ should turn out to have an immensely complicated internal composition.

Followup to:  Angry Atoms

After yesterday's post, it occurred to me that there's a much simpler example of reductionism jumping a gap of apparent-difference-in-kind: the reduction of heat to motion.

Today, the equivalence of heat and motion may seem too obvious in hindsight—everyone says that "heat is motion", therefore, it can't be a "weird" belief.

But there was a time when the kinetic theory of heat was a highly controversial scientific hypothesis, contrasting to belief in a caloric fluid that flowed from hot objects to cold objects.  Still earlier, the main theory of heat was "Phlogiston!"

Suppose you'd separately studied kinetic theory and caloric theory.  You now know something about kinetics: collisions, elastic rebounds, momentum, kinetic energy, gravity, inertia, free trajectories.  Separately, you know something about heat:  Temperatures, pressures, combustion, heat flows, engines, melting, vaporization.

Not only is this state of knowledge a plausible one, it is the state of knowledge possessed by e.g. Sadi Carnot, who, working strictly from within the caloric theory of heat, developed the principle of the Carnot cycle—a heat engine of maximum efficiency, whose existence implies the second law of thermodynamics.  This in 1824, when kinetics was a highly developed science.

Suppose, like Carnot, you know a great deal about kinetics, and a great deal about heat, as separate entities.  Separate entities of knowledge, that is: your brain has separate filing baskets for beliefs about kinetics and beliefs about heat.  But from the inside, this state of knowledge feels like living in a world of moving things and hot things, a world where motion and heat are independent properties of matter.

Now a Physicist From The Future comes along and tells you:  "Where there is heat, there is motion, and vice versa.  That's why, for example, rubbing things together makes them hotter."

Followup to:  Reductionism, Explaining vs. Explaining Away, Fake Reductionism

Back to our original topic:  Reductionism, which (in case you've forgotten) is part of a sequence on the Mind Projection Fallacy.  There can be emotional problems in accepting reductionism, if you think that things have to be fundamental to be fun.  But this position commits us to never taking joy in anything more complicated than a quark, and so I prefer to reject it.

To review, the reductionist thesis is that we use multi-level models for computational reasons, but physical reality has only a single level.  If this doesn't sound familiar, please reread "Reductionism".

Today I'd like to pose the following conundrum:  When you pick up a cup of water, is it your hand that picks it up?

Most people, of course, go with the naive popular answer:  "Yes."

Recently, however, scientists have made a stunning discovery:  It's not your hand that holds the cup, it's actually your fingers, thumb, and palm.

Yes, I know!  I was shocked too.  But it seems that after scientists measured the forces exerted on the cup by each of your fingers, your thumb, and your palm, they found there was no force left over—so the force exerted by your hand must be zero.

    The torches that lit the narrow stairwell burned intensely and in the wrong color, flame like melting gold or shattered suns.
    192... 193...
    Brennan's sandals clicked softly on the stone steps, snicking in sequence, like dominos very slowly falling.
    227... 228...
    Half a circle ahead of him, a trailing fringe of dark cloth whispered down the stairs, the robed figure itself staying just out of sight.
    239... 240...
    Not much longer, Brennan predicted to himself, and his guess was accurate:
    Sixteen times sixteen steps was the number, and they stood before the portal of glass.
    The great curved gate had been wrought with cunning, humor, and close attention to indices of refraction: it warped light, bent it, folded it, and generally abused it, so that there were hints of what was on the other side (stronger light sources, dark walls) but no possible way of seeing through—unless, of course, you had the key: the counter-door, thick for thin and thin for thick, in which case the two would cancel out.
    From the robed figure beside Brennan, two hands emerged, gloved in reflective cloth to conceal skin's color.  Fingers like slim mirrors grasped the handles of the warped gate—handles that Brennan had not guessed; in all that distortion, shapes could only be anticipated, not seen.
    "Do you want to know?" whispered the guide; a whisper nearly as loud as an ordinary voice, but not revealing the slightest hint of gender.
    Brennan paused.  The answer to the question seemed suspiciously, indeed extraordinarily obvious, even for ritual.

Followup to:  Bind Yourself to Reality

For many years before the Wright Brothers, people dreamed of flying with magic potions.  There was nothing irrational about the raw desire to fly.  There was nothing tainted about the wish to look down on a cloud from above.  Only the "magic potions" part was irrational.

Suppose you were to put me into an fMRI scanner, and take a movie of my brain's activity levels, while I watched a space shuttle launch.  (Wanting to visit space is not "realistic", but it is an essentially lawful dream—one that can be fulfilled in a lawful universe.)  The fMRI might—maybe, maybe not—resemble the fMRI of a devout Christian watching a nativity scene.

Should an experimenter obtain this result, there's a lot of people out there, both Christians and some atheists, who would gloat:  "Ha, ha, space travel is your religion!"

But that's drawing the wrong category boundary.  It's like saying that, because some people once tried to fly by irrational means, no one should ever enjoy looking out of an airplane window on the clouds below.