Monthly Archives: April 2008

Configurations and Amplitude

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This post is part of the Quantum Physics Sequence.
Previously in series:  Quantum Explanations

So the universe isn’t made of little billiard balls, and it isn’t made of crests and troughs in a pool of aether…  Then what is the stuff that stuff is made of?

(Diagrams stolen from qubit.org and edited for my purposes.)

Fig1_4 In Figure 1, we see, at A, a half-silvered mirror, and two photon detectors, 1 and 2.

Early scientists, when they ran experiments like this, became confused about what the results meant.  They would send a photon toward the half-silvered mirror, and half the time they would see the detector at 1 click, and the other half the time they would see the detector at 2 click.

The early scientists – you’re going to laugh at this – thought that the silver mirror deflected the photon half the time, and let it through half the time.

Ha, ha!  As if the half-silvered mirror did different things on different occasions!  I want you to let go of this idea, because if you cling to what early scientists thought, you will become extremely confused.  The half-silvered mirror obeys the same rule every time.

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Prevention Costs

More prevention will not cut health care costs.  Tuesday’s Post:

Most of us naturally assume that preventing a disease is cheaper than waiting for the disease to appear and then treating it. That belief is especially dear to politicians, who often view prevention as an underused weapon in the battle against health-care costs. …

In 1986, a health economist named Louise B. Russell published "Is Prevention Better Than Cure?," in which she concluded that prevention activities tend to cost more than they save. Since the book’s appearance, her observation has been borne out by studies of hundreds of interventions — everything from offering mammograms to all women and prescribing drugs to people with high cholesterol to requiring passenger-side air bags in cars and shortening the response time of ambulances. …

For example, Australian researchers tried out a program in which general practitioners watched a video and read a booklet about how to help their patients lower their heart attack risk. The patients were then given a series of videos and a self-help booklet on the same topic.  How cost-effective is this instruction? When it is provided for women at low risk of heart disease, $9.8 million has to be spent for every year of life saved in the prevention of premature heart attack deaths. …

Some disease-preventing activities … save money, although they are relatively rare. Childhood vaccinations are the classic examples. … Providing a single colonoscopy to men 60 to 64 years old also saves money. …

Similar to the finding that prevention rarely saves money is the calculation that people in good health probably rack up higher lifetime medical costs than their less-healthy brethren.  The reason?  Healthy people tend to live longer.

Added:  I’m mentioned in today’s NYT re prediction markets, alas again as the extremist.

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Quantum Explanations

This post is part of the Quantum Physics Sequence.

I think I must now temporarily digress from the sequence on zombies (which was a digression from the discussion of reductionism, which was a digression from the Mind Projection Fallacy) in order to discuss quantum mechanics.  The reasons why this belongs in the middle of a discussion on zombies in the middle of a discussion of reductionism in the middle of a discussion of the Mind Projection Fallacy, will become apparent eventually.

It’s a sequence that has been weighing on my mind, demanding to be written, for a quite a long time.  Years.  This seems like a good time to insert it.

I wrote the "Intuitive Explanation of Bayesian Reasoning" because people were complaining that Bayes’s Theorem was "counterintuitive" – in fact it was famously counterintuitive – and this did not seem right.  The equation just did not seem complicated enough to deserve the fearsome reputation it had.  So I tried explaining it my way, and I did not manage to reach my original target of elementary school students, but I get frequent grateful emails from formerly confused folks ranging from reporters to outside academic college professors.

I am not a physicist, and physicists famously hate it when non-professional-physicists talk about QM.  But I do have some experience with explaining mathy things that are allegedly "hard to understand".

Besides, as a Bayesian, I don’t believe in phenomena that are inherently confusing.  Confusion exists in our models of the world, not in the world itself.  If a subject is widely known as confusing, not just difficult… you shouldn’t leave it at that.  It doesn’t satisfice; it is not an okay place to be.  Maybe you can fix the problem, maybe you can’t; but you shouldn’t be happy to leave students confused.

The first way in which my introduction is going to depart from the traditional, standard introduction to QM, is that I am not going to tell you that quantum mechanics is supposed to be confusing.

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Inhuman Rationality?

We seem comfortable celebrating those who practice complex statistical analysis, even if only one in a thousand can do so.  And the one in a billion genius celebrated for greatly improving our understanding or practice of statistics, or other rationality, seems to us an epitome of the best in humanity.  Who would call such exemplars "inhuman"?

But when rationality seems to require not rare celebrated abilities, but common despised tendencies, suddenly many complain rationality is "inhuman."  For example, many balk at my suggestion that rationality requires us to be more conformist in our beliefs, deferring more to others’ opinions, even if in conversation we explore different evidence and analyzes.  Yet conformity is widespread and most people have far more diverse word-opinions than betting-opinions.  I’d guess far more than one in a thousand humans realize something close to the degree of conformity I’m suggesting. 

It seems to me that the real issue here is not humanity but social status.  We are eager to achieve aspects of rationality that get high social status, but not those that get low status.  To gain high status, we don’t mind moving far out into the tails of the distribution of human features, but if low status is a prospect we suddenly express grave concern about moving out into the "inhuman" tails.

For example, when I said

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Belief in the Implied Invisible

Followup toThe 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…)

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Endearing Sincerity

Honestly demands I admit that soon after penning that sincerity is overrated, and that fiction typically distracts from reality, I fell in love with a fictional movie celebrating sincerity:  Once, depicting people who really love music, more than money or sex or anything.  It resonated with my cherished memories of being a teen religious cultist (~’74), and a young adult in an idealistic tech community exploring the web, nanotech, and more (’84-93).  People feel tied especially tied to others with whom they share a deep love of an unpopular or unrewarded hobby.  When other rewards loom larger, such as money, fame, sex, etc., we are less sure of our associates’ motives.

I’m lucky to be a professor, but alas since this job pays money and prestige, most of the people I deal with seem to primarily seek such rewards.  Gordon Tullock (office next to mine) in 1966:

An investigator wholly motivated by induced curiosity is different in many ways from one motivated by either curiosity or a desire to make practical application of new knowledge.  … If he could establish and maintain his reputation, and hence his job, by reporting completely fictional discoveries, this would accomplish his end.  … Those administering a system of induced research …  must make certain that [such] investigators are induced to pay attention to the real world.  As we have seen, the actual system used by administrators in our present setup is simply to count the number of papers published by a man in journals of various degrees of reputation.  The reputation of the journals, again as we have seen, is determined by their readers.  … A self-perpetuating process might be set in motion in which a journal read only by people motivated by induced curiosity gradually slipped away from reality in the direction of superficially impressive but actually easy research projects.  In most sciences this does not happen. … One symptom of the existence of this condition is the development of very complex methods of treating subject which can be readily handled by simple methods (pp56-57).

It is worse that Tullock thought.  Few academic topics are dominated by topic lovers; intellectual progress is largely a side effect of prestige seeking.  And even "sincere" topic love is directed by our ancient evolved coding designed to gain us more basic rewards.  But even so, I miss being part of a community primarily tied by a common love of a topic or activity, vs. wider prestige or money.  Not sure how consistent this is with anything else I’ve written.

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GAZP vs. GLUT

Followup toThe 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.

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The Generalized Anti-Zombie Principle

Followup toZombies! Zombies?

"Each problem that I solved became a rule which served afterwards to solve other problems."
        — Rene Descartes, Discours de la Methode

"Zombies" are putatively beings that are atom-by-atom identical to us, governed by all the same third-party-visible physical laws, except that they are not conscious.

Though the philosophy is complicated, the core argument against zombies is simple:  When you focus your inward awareness on your inward awareness, soon after your internal narrative (the little voice inside your head that speaks your thoughts) says "I am aware of being aware", and then you say it out loud, and then you type it into a computer keyboard, and create a third-party visible blog post.

Consciousness, whatever it may be – a substance, a process, a name for a confusion – is not epiphenomenal; your mind can catch the inner listener in the act of listening, and say so out loud.  The fact that I have typed this paragraph would at least seem to refute the idea that consciousness has no experimentally detectable consequences.

I hate to say "So now let’s accept this and move on," over such a philosophically controversial question, but it seems like a considerable majority of Overcoming Bias commenters do accept this.  And there are other conclusions you can only get to after you accept that you cannot subtract consciousness and leave the universe looking exactly the same.  So now let’s accept this and move on.

The form of the Anti-Zombie Argument seems like it should generalize, becoming an Anti-Zombie Principle.  But what is the proper generalization?

Let’s say, for example, that someone says:  "I have a switch in my hand, which does not affect your brain in any way; and iff this switch is flipped, you will cease to be conscious."  Does the Anti-Zombie Principle rule this out as well, with the same structure of argument?

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Anxiety about what is true

Robin links to an article about apparent manipulation of the medical process by drug manufacturers, dealing particularly with the drug Fosamax which is supposed to improve bone strength. The article raises the possibility that many modern diseases don’t exist at all but are the creation of the pharmaceutical industry to give them tools to sell more drugs.

My wife used to take Fosamax, so this was a topic of interest to me. To learn more, I did a search on scholar.google.com for “fosamax hip-fracture”. It looks to me like most of the hits are pretty favorable to the drug, but how much does that really prove?

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Ramone on Knowing God

Riffing off Eliezer on consciousness, here is (my alter-ego) Ramone on spirituality: 

We are souls who know we are spiritual.  Since we can conceive of mere non-soul "animals," physical bodies without spirit, spirituality must be a non-physical "something more."  (Until someone proves this is not logically possible, we assume it is.)  We call this something more "God", or at least a part of God.  So our full selves, which we call a "soul", contains both a God-part and an animal-part.

We know God is real and that we are not animals.  Skeptics ask: how do we know?  Our God-part, being God and spirit, can directly see God and that it is spiritual.  What could be simpler?  But skeptics persist; they correctly note that it may well be that the spiritual, or God, part of our soul has no causal influence on the body, or animal, part of our soul.  If so, they wonder, how could our animal-parts know about God?  Their mistake is to think that animals "know" anything – clearly only souls know anything.  We obviously use words like "know" and "think" to refer only to high noble things, not base lowly things; there is only a superficial analogy between signal processing in animal bodies and the what spiritual souls know or think.   

But base skeptics persist with their base analogy, asking how our animal parts can process signals to see they are part of a soul with a spiritual part?  After all, skeptics sneer, if spirits have no causal influence on bodies, and if in some alternate evil universe our bodies were in fact not parts of souls but lone animals, would not those bodies process the same signals the same way?  If so, would they not then incorrectly "think", with their animal pseudo-thoughts, that they were part of a soul?  Yes, such imagined abominations could have abominable pseudo-thoughts, but since in our actual universe we actually are spiritual souls, why is it so strange that we actually think that we are what we in fact are?

To belabor the obvious, Ramone’s God argument is intended to mirror Chalmer’s qualia argument.  Accept both or neither, or show the difference.  (FYI, Chalmers and I exchanged about twenty emails last fall.)

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