Monthly Archives: March 2008

Heat vs. Motion

Followup toAngry 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 hindsighteveryone 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."

Continue reading "Heat vs. Motion" »

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Against News

Bryan Caplan raises a neglected but important issue:  are important issues neglected for news of the moment?  Bryan quotes Delos Wilcox from 1900:

But we must deplore and, so far as possible, overcome the evils of habitual newspaper reading. These evils are, chiefly, three: first, the waste of much time and mental energy in reading unimportant news and opinions, and premature, untrue, or imperfect accounts of important matters; second, the awakening of prejudices and the enkindling of passions through the partisan bias or commercial greed of newspaper managers; third, the loading of the mind with cheap literature and the development of an aversion for books and sustained thought.

Bryan also quotes Thomas Jefferson:

Avertisements contain the only truths to be relied on in a newspaper. …
I do not take a single newspaper, nor read one a month, and I feel myself infinitely the happier for it. …
The man who reads nothing at all is better educated than the man who reads nothing but newspapers.

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Angry Atoms

Followup toHand vs. Fingers

Fundamental physics – quarks ‘n stuff – is far removed from the levels we can see, like hands and fingers.  At best, you can know how to replicate the experiments which show that your hand (like everything else) is composed of quarks, and you may know how to derive a few equations for things like atoms and electron clouds and molecules.

At worst, the existence of quarks beneath your hand may just be something you were told.  In which case it’s questionable in one what sense you can be said to "know" it at all, even if you repeat back the same word "quark" that a physicist would use to convey knowledge to another physicist.

Either way, you can’t actually see the identity between levels – no one has a brain large enough to visualize avogadros of quarks and recognize a hand-pattern in them.

But we at least understand what hands do.  Hands push on things, exert forces on them.  When we’re told about atoms, we visualize little billiard balls bumping into each other.  This makes it seem obvious that "atoms" can push on things too, by bumping into them.

Now this notion of atoms is not quite correct.  But so far as human imagination goes, it’s relatively easy to imagine our hand being made up of a little galaxy of swirling billiard balls, pushing on things when our "fingers" touch them.  Democritus imagined this 2400 years ago, and there was a time, roughly 1803-1922, when Science thought he was right.

But what about, say, anger?

How could little billiard balls be angry?  Tiny frowny faces on the billiard balls?

Continue reading "Angry Atoms" »

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Hand vs. Fingers

Followup toReductionism, 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.

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Impotence of Belief in Bias

A new study from Leibniz University Hannover finds that the 1/3 of German professional fund managers who believe human biases to be important in financial markets have better calibrated estimates and rely more on momentum and contrarian strategies, but otherwise think and act like other fund managers:

[A] literature in psychology … has clearly revealed the "bias blind spot" (Pronin et al., 2002), i.e. the belief that one’s own judgments are less susceptible to biases than the judgments of others. … [Among] professional … fund managers we differentiate … "endorsers" of behavioral finance … [who] believe that the approach of behavioral finance truly reflects decision behavior in fund management (and who know the key messages of behavioral finance well) … [and] non-endorsers. … We have surveyed [104] fund managers in Germany and classify them according to their self-assessment into these two groups. …

Whereas [the 37] endorsers recognize significantly stronger behavioral finance effects in other fund managers’ behavior than non-endorsers, the perception of their own behavior is largely unaffected by their insights.  When endorsers’ are asked about their own behavior with respect to items being linked to behavioral finance, such as hindsight bias or disposition effect, they answer as non-endorsers do. However, there is one exception … Endorsers show less miscalibration with respect to forecasting the interval of a stock index. … We [also] find … endorsers rely more on momentum and contrarian [versus buy-and-hold] strategies. … Endorsement … is not closely related to personal characteristics, such as being older or holding a better position etc.

Even for those with strong incentives to correct for biases, knowing about and believing in biases has influenced their decisions little, and not obviously to their benefit.  This suggests that we focus not on trying to correct our personal biases but instead on identifying and promoting institutions, such as prediction markets, to reduce biases. 

Hat tip to Zubin Jelveh and Tyler Cowen. 

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Initiation Ceremony

    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.

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Cash Increases Accuracy

From the current New Scientist:

In an experiment dubbed "Cola Wars", [Nick Epley] conducted a taste test with a twist: he told participants which cola was Coke and which was Pepsi before tasting began. After tasting, all they had to do was estimate what percentage of their friends would be able to distinguish between the two in a blind taste test. Studies show that people’s ability to do this is no better than chance – so an answer around 50 per cent would be right. What Epley found was intriguing. When he motivated volunteers to give a considered response – by offering them a cash payment – their answers tended to be close to 50 per cent. Subjects who were not paid, however, seemed to answer with an egocentric bias: since they knew which cola was which, they assumed that a high proportion of their friends would guess correctly (Journal of Personality and Social Psychology, vol 87, p 327).  For Epley, the finding supports his idea that putting yourself inside the head of another person and considering their perspective requires a cognitive effort that simple egocentric judgements do not.

Make no mistake: stronger incentives often (though not always) make us see more clearly.

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To Spread Science, Keep It Secret

Followup toJoy in Discovery, Bind Yourself to Reality, Scientific Evidence, Scarcity

Sometimes I wonder if the Pythagoreans had the right idea.

Yes, I’ve written about how "science" is inherently public.  I’ve written that "science" is distinguished from merely rational knowledge by the in-principle ability to reproduce scientific experiments for yourself, to know without relying on authority.  I’ve said that "science" should be defined as the publicly accessible knowledge of humankind.  I’ve even suggested that future generations will regard all papers not published in an open-access journal as non-science, i.e., it can’t be part of the public knowledge of humankind if you make people pay to read it.

But that’s only one vision of the future.  In another vision, the knowledge we now call "science" is taken out of the public domain – the books and journals hidden away, guarded by mystic cults of gurus wearing robes, requiring fearsome initiation rituals for access – so that more people will actually study it.

I mean, right now, people can study science but they don’t.

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Ancient Political Self-Deception

From Gene Expression:

There are certain things which are sacred, certain lines you don’t cross. … I was thinking about [this] a few months ago when I read Rome & Jerusalem: A Clash of Ancient Civilizations and God’s Rule – Government and Islam.  You see, the ancient Romans and Muslims did not have kings. Kings were tyrants, and the early Roman and Islamic polities rejected such tyranny on principle. So of course, instead of kings, the Roman Empire was headed by an emperor, while the Muslims had caliphs. Get it? When Augustus defeated Mark Antony and Cleopatra the official narrative was that the doughty republican traditions of Rome had bested once more the oriental despotism of the Hellenistic world, with their Greek kings and queens. Similarly, the righteous AbbasidsUmayyads. In its place they established a genuine Islamic state which was guided by the traditions of the community as opposed to profane naked autocracy. Right….

As you can see here, the extent of the self-deception and semantic delusion is really humorous. Now, it is true that the early emperors of Rome tended to keep up the illusion that they were simply stewards of the Roman Republic with some verisimilitude. Augustus’ shtick was that his was a restorationist project; he was no dictator or king, just the First Citizen. Similarly, the early Abbasids were ostensibly bringing the vision of the Islamic community to its true fulfillment (especially the Shia party), whereas the Umayyads had been worldly Arab tribalists more in keeping with the values of the jahiliya. … Muslim soldiers were enraged and shocked when the conqueror of Spain allowed his Visigothic wife to convince him to don a crown and so indicate kingship; they accused him of becoming a Christian.

I’ve been saying for years that people prefer democracy mainly because they think it raises their social status – being ruled by a king makes you lower status relative to people who "rule themselves."  We can’t quite fool ourselves into thinking a king is just a "steward", but we apparently can think we really rule because we elect our rulers.

Added 2Apr:  Nazi Hermann Göring:

Oh, [democracy] is all well and good, but, voice or no voice, the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country.  [HT Caplan

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What follows is taken primarily from Robert Cialdini’s Influence: The Psychology of Persuasion.  I own three copies of this book, one for myself, and two for loaning to friends.

Scarcity, as that term is used in social psychology, is when things become more desirable as they appear less obtainable.

  • If you put a two-year-old boy in a room with two toys, one toy in the open and the other behind a Plexiglas wall, the two-year-old will ignore the easily accessible toy and go after the apparently forbidden one.  If the wall is low enough to be easily climbable, the toddler is no more likely to go after one toy than the other.  (Brehm and Weintraub 1977.)
  • When Dade County forbade use or possession of phosphate detergents, many Dade residents drove to nearby counties and bought huge amounts of phosphate laundry detergents.  Compared to Tampa residents not affected by the regulation, Dade residents rated phosphate detergents as gentler, more effective, more powerful on stains, and even believed that phosphate detergents poured more easily.  (Mazis 1975, Mazis et. al. 1973.)

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