Saturday, June 08, 2019

How do we know that quantum randomness is really random?

Since the dawn of quantum physics, the Born rule has been the cause of much consternation and gnashing of dentition, with Einstein famously complaining that God doesn't play dice.    Was Einstein right?  Is the apparent randomness of quantum measurements an illusion?  Are the results of quantum measurements actually deterministic but dependent on some hidden state that we simply don't have access to?  In other words, is the apparent randomness a reflection of a fundamental truth about objective reality, or simply a reflection of our ignorance?  And how can we possibly know for sure?  After all, ignorance, by its very nature, does not yield readily to introspection.

For the purposes of this discussion let's consider an idealized quantum experiment that has only two outcomes.  You can think of this as measuring the spin of an electron or the polarization of a photon.  Again, the details don't matter.  All that matters is that there are two possible outcomes (let's call them A and B).  Let's further suppose just for the sake of simplicity that both outcomes are equally likely.

So we do a bunch of experiments and collect a bunch of data.  This data is in the form of a sequence of A's and B's, each corresponding to the outcome of one instance of the experiment.  We analyze this sequence and it looks random.  We apply a bunch of statistical tests and they call come back and say, yep, this is a random sequence.  We wrack our brains to try to come up with a way to predict the outcome of the next experiment with odds better than chance and we fail.  Does that prove that this sequence is in fact random?

No, of course not.  We can trivially reproduce the exact same sequence in a purely deterministic way simply by playing back the record of the previous outcomes!  So how can we know that the sequence wasn't generated this way the first time around?  How do we know that there isn't a deterministic process out there in the universe somewhere that has pre-ordained the outcome of every quantum measurement we ever make?

It would seem that the fact that any sequence of experimental outcomes could be generated by playing back a record of them shows that we can never be sure that it wasn't actually done that way.  But this is wrong, and in fact it is easy to see exactly how and why it is wrong.  You might want to stop here and see if you can figure it out on your own.

Here's a clue: if the sequence of experimental outcomes was the result of simply replaying a record, or indeed of any kind of deterministic computational process (of which replaying a record is just one trivial example), we should be able to find evidence of that somewhere.  In order to make a record we have to store information somewhere.  In order to make a computational process we have to make a computer.  If that information was stored in any kind of straightforward way, and in particular (no pun intended) if that information is stored in any kind of physical artifact made of atoms then we should be able to find it.  Or at least we should be able to find some evidence that it exists.

But we can't.  And if you think about it, it is absolutely impossible for such an artifact to exist.  Why? Because it would have to store the outcome not just for the experiments that we actually do, but for any experiment that we could possibly do, and it would have to store those outcomes for every particle in the universe on which we might choose to perform an experiment including the particles that make up the artifact that is supposedly storing all this information!

Now, this is not yet an ironclad proof because there is one remaining possibility.  We don't actually have to store a separate record of the results of our experiments in order to be able to reproduce the same sequence of results.  It is enough simply to hang on to the particles themselves.  Once we have made a measurement on a particle, if we make the same measurement again we will get the same result.  So it's possible that the information that determines the results of experiments performed on particles is stored in the particles themselves.

The usual way to dispense with this possibility is to invoke Bell's theorem and to point out that it rules out local hidden variables.  But there's a more elementary (and, I think, more compelling) argument.

It is true that if we do the same experiment on a single particle twice in a row we will get the same result.  But nothing constrains us from doing different experiments on a single particle.  We could, for example, measure the position of a particle, and then its momentum, and then its position again, and then its momentum again.  If we do this, every result will be (apparently) random, completely disconnected from anything that has gone before.  And (and this is key) we can do this forever.  We can perform an infinite (well, OK, unbounded) number of measurements on one particle.  For the results to be deterministic, the state of the particle would have to store an infinite (and this time I really do mean infinite) amount of information.

Well, how do we know that this is not in fact the case?  Bohmian mechanics, for example, is a theory of exactly this sort.  In Bohmian mechanics, particles have positions, and (it turns out) all of the potentially infinite information that can be read out (eventually) via quantum measurements is encoded in the initial position of the particle.  This is possible because the position of the particle is metaphysically exact, represented by an actual real number with an infinite number of digits in its expansion and hence can contain an infinite amount of information.

How do we know that this is not what is actually happening?

Well, we don't.  Bohmian mechanics reproduces the predictions of quantum mechanics exactly so there is no way to settle the question experimentally.  There are nonetheless three good reasons to reject Bohm as an adequate explanation of physical reality.

First, the way that Bohm handles spin is really weird, bordering on the perverse.  Again for those who don't know, spin is a property of certain particles (mainly electrons) that can be measured and always produces one of two results (usually called "up" and "down" even though these don't actually have any physical significance).  In Bohmian mechanics, the only metaphysically real property that a particle has is position (and hence also velocity, which is just the time derivative of the position as in classical mechanics).  Spin is not part of the metaphysically real state of a particle.  When you think you're measuring spin, you're actually measuring the particle's position (because that's all there is) but the wave function (the "pilot wave", the thing that's pushing the particle around) conspires to move the particle through spin-measurement apparatus in just such a way that it looks as if the particle has spin, even though it really doesn't.  Bohmian mechanics is quite literally a cosmic conspiracy theory.

Second, Bohmian mechanics is causally non-local.  When you do an EPR-type experiment Bohm says that the underlying metaphysical reality is different depending on the order in which you perform the two measurements.  But according to relativity, the order of space-like separated events is not well defined.  So in order to extract an unambiguous description of physical reality from Bohm you have to arbitrarily assign an order to space-like separated events (the technical term for this is choosing a foliation).  There is no way to tell which foliation is correct (if there were then you could experimentally falsify relativity) so the choice is arbitrary.  But (and this is the crucial point) the fact that it is arbitrary completely undermines the whole point of adopting Bohmian mechanics to begin with, which was to provide a complete description of physical reality that was compatible with classical intuition.  Instead of one description of reality you have an arbitrary number of them, one for each possible foliation, and there's no way to tell which one is actually correct.

Third, although Bohm hangs his hat entirely on the physical reality of particle positions, it is fundamentally impossible to know what the position of a particle actually is.  Remember, when you measure the spin of a particle, on Bohmian mechanics you are not really measuring spin, you are really measuring position (because that's all there is).  Well, it turns out that when you measure position you aren't really measuring position either.  The only kind of measurement you can make is one that tells you whether or not the particle was inside or outside a particular (no pun intended) finite region of space.  The actual position of a particle cannot be measured.  So the one thing that Bohm advances as a description of physical reality turns out to be the operational equivalent of an invisible pink unicorn (IPU) — a thing that is posited to exist but which, by its very nature, can never be measured.

There is an even simpler argument to demonstrate the non-measurability of Bohmian positions: a measurement can only ever produce a finite amount of information, but the information encoded in the particle's actual metaphysical position is necessarily infinite (because it has to encode the results of all possible future measurements).  So the results of position measurements must contain errors.

And this is the crux of the matter: it just turns out as a matter of physical fact that a single particle can produce what appears to be an unbounded amount of information.  There are only two possibilities: either that information is generated on the fly ex nihilo, (that is, it's "really random") or it is stored somewhere.  But no one has been able to identify any possible repository in the physical world where that information could be stored.  In fact, QM fundamentally depends on this not being possible!  Interference effects only manifest themselves if there is no possible way to distinguish two different states of a system.  But to contain information, a system must have distinguishable states -- that's what information means!  To be compatible with the data, a hypothetical repository of that information must necessarily be an IPU.  Any theory where the existence of such a repository was experimentally demonstrable would not be compatible with QM.

Thursday, June 06, 2019

Quantum transitions take time. This is not news.

A number of people have asked me to weigh in on this story in Quanta Magazine (based on this paper [PDF version] and also reported in this press release from Yale, and several other popular outlets.)

Here's how Quanta breathlessly reported the result:
When quantum mechanics was first developed a century ago as a theory for understanding the atomic-scale world, one of its key concepts was so radical, bold and counter-intuitive that it passed into popular language: the “quantum leap.” Purists might object that the common habit of applying this term to a big change misses the point that jumps between two quantum states are typically tiny, which is precisely why they weren’t noticed sooner. But the real point is that they’re sudden. So sudden, in fact, that many of the pioneers of quantum mechanics assumed they were instantaneous. 
A new experiment shows that they aren’t.
This is mostly hype.  While it is true that in the very early days of quantum mechanics some researchers (notably Niels Bohr) thought that quantum transitions were instantaneous, the fact that they aren't has been known for decades.  What is new here is that this is the first time that this fact has been demonstrated experimentally.  I don't want to detract from the technical accomplishment here in any way, it's a truly impressive experiment.  But it's not the kind of conceptual breakthrough that the Quanta story implies.  It's a totally expected result.

It is natural to conclude from the fact that energy states are quantized that the transition between them must happen instantaneously.  Consider a system that transitions from energy state 0 to an adjacent energy state 1 (in some suitable units). It can't do it via a smooth transition between intermediate energy levels because these are physically impossible (that the whole point of quantum mechanics).  So if a system is going to transition from 0 to 1 without occupying any energy state in between, the transition must be instantaneous, right?

Wrong.  There is a different kind of "smooth" transition that a system can make between the 0 and 1 states, and that is via a superposition of the two states.  Just as a particle can be in two different locations at the same time, it can be in two different energy states at the same time.  To go smoothly from 0 to 1, the system transitions through a series of superpositions of both states, i.e. it starts out entirely in state 0, and then transitions smoothly to being mostly in state 0 and a little bit in state 1, to being half in each state, to being mostly in 1 and a little bit in 0, to being entirely in 1.  This has been known for decades, and is predicted by the math.  You can even predict how fast the transition happens.  For most common physical processes, like an atom absorbing or emitting a photon, the transition is really fast.  But it's not instantaneous.

The tricky part is not figuring out that quantum transitions take time (well, OK, figuring it out is tricky too, but it's easy once you know how) but designing an experiment that demonstrates that the theory is correct.  This is because any straightforward measurement of the energy of the system will always produce a result that shows the system is in one state or the other.  The existence of superpositions can only be demonstrated indirectly, usually through interference effects.  So to demonstrate the non-instantaneous nature of a quantum transition you have to do two things: first, you need to actually catch a system during a (typically very fast) transition and second, you need to come up with a way of getting the system to interfere with itself (or producing some other indirect effect that would not occur but for the existence of a superposition).  That's what Minev et al. did.

The way they did it is really cool, but the advance here is an experimental one, not a theoretical one.  They used a superconductor to produce a macroscopic quantum system that behaved like an atom in that it had a small number of discrete energy levels that it could transition between.  Then they "tickled" this "atom" with microwaves and observed that the resulting response exhibited the kind of interference effects that would be expected if if were transitioning through superposition states.  It's very cool, and a very impressive technical achievement, but it is in no way unexpected or surprising.

Saturday, May 25, 2019

An open letter to Christian supporters of Donald Trump

Dear Christian supporters of Donald Trump:

I occasionally hear some of you complain that we west-coast liberals don't take you seriously.  Well, if you want me to take you seriously, then one of you is going to have to explain to me how this is not bearing false witness against your neighbor:
U.S. President Donald Trump, engaged in personal attacks on House of Representatives Speaker Nancy Pelosi, retweeted a heavily edited video that falsely claimed the Democratic leader had difficulty speaking to reporters.
And, while I'm at it, maybe one of you would be good enough to explain to me how you square your support for Trump with Matthew 19:24?  Are there some really tiny camels out there (or some really big needles) that I don't know about?

Seriously, I want to understand you and reach a place of mutual respect.  But you sure aren't making it easy for me.


Saturday, May 18, 2019

If a fetus is a person...

Carliss Chatman raises some very interesting questions about the logical consequences of fetal personhood. To which I would like to add: if life begins at conception, and hence an embryo is a person, can I adopt a frozen embryo and write them off as a dependent on my taxes?  No, seriously, I want to know.  This could be very lucrative.

The mother of all buyer's remorse

[Part of an ongoing series of exchanges with Jimmy Weiss.]

Jimmy Weiss responded to my post on teleology and why I reject Jimmy's wager (not to be confused with Pascal's wager) nearly a month ago.  I apologize to Jimmy and anyone who has been waiting with bated breath for my response (yeah, right) for the long delay.  Somehow, life keeps happening while I'm not paying attention.

So, finally, to the task at hand.  Jimmy writes:
Ron presents the right kind of argument here.  He argues that an infinite reward is impossible, because, in his words, “an infinite reward is fundamentally incompatible with human nature.”  Ron “can hardly imagine a worse fate than to be immortal.” 
There is an important sense in which I quite agree with Ron’s statement here.  I absolutely agree that “an infinite reward is fundamentally incompatible with human nature.”  Human beings are, in the core of our nature: ignorant, proud, lazy, fearful, and restless.
I'm happy to hear that I'm presenting "the right kind of argument" and that we've found a bit of common ground.  That is my overarching goal in this effort, and for an atheist to find any common ground with a YEC is something I would have given you long odds against not so long ago.  (For those of you following this exchange, I think it's worth noting the fact that the age of the earth has not entered into the discussion at all.  I think that's salient.)

I have only a minor quibble with Jimmy's characterization of the situation: yes, humans are ignorant, proud, lazy (at least I am) fearful, and restless.  But I would not say that these things are in the core of our nature.  What is at the core of our nature is that we are living things.  Like all living things, we were born, and we will die, and yes that kind of sucks, but that's the way it is.  Would I like to live longer that I likely will?  Yeah, probably.  Would I like to live forever?  No.  Absolutely not.
Ron’s argument for the impossibility of the infinitude of God’s reward depends on the fixity of our nature.  But as far as I can see, there is no reason to assume fixity concerning those aspects of our nature that impede our ability to perceive, pursue, and enjoy goodness.
My argument against the desirability of immortality doesn't demand that our nature remain fixed.  I'm a very different person today than I was 10, 20, 30... years ago.  But I do think it's important that heaven not require us to change so much that we cease to be human, and the more I think about it, the more I come to believe that that is exactly what it does require.  I don't see any way that we could be immortal and still be human.  Mortality is an essential part of being human, indeed an essential part of being alive at all.

More than that, I want to argue here that being imperfect is an essential part of being human.  Consider the first adjective that Jimmy chose to characterize us: ignorant.  I imagine he intended it to be pejorative, and of course he's right.  Ignorance is not generally a good thing.  We should not seek to be ignorant, nor should we seek to remain ignorant.  The quest for knowledge is a noble one, one might even say that this quest is a core aspect of our nature.

But imagine what it would be like if we were to actually succeed in our quest not to be ignorant.  Ignorance means to lack knowledge, so by definition, to be not ignorant is to not lack any knowledge.  It is to be omniscient, to know everything.  In that respect we would become like God.

Would that be a good thing?  I don't know, but I do know this: if it were to happen, we would lose an essential aspect of our humanity because there would no longer be any point in engaging in our quest for knowledge.  If we succeed in totally eradicating ignorance, there would no longer be any point in reading a book; everyone would already know the contents of all possible books.  The value of reading a book is entirely dependent on ignorance of its contents.  If you are not ignorant of the contents of a book that means that you already know its contents.  You have memorized it word-for-word.  If you haven't, if there is any lack of knowledge about the contents of the book for which you have to actually go back and refer to the book itself, then you are still ignorant, at least of that aspect of the book's contents.

So a non-ignorant being cannot read a book.  A non-ignorant being cannot engage in a conversation with another non-ignorant being because both of them would already know what the other was going to say.  The whole point of reading books and engaging in conversations is to communicate information and that presupposes that the information is lacking somewhere.  Ignorance is necessary if communication is to have any point at all.

Let's consider Jimmy's next two adjective: "proud" and "lazy".  Again, I'm pretty sure he intended these to be pejorative.  But I am lazy, and I am proud of being lazy.  My laziness has been a powerful motivator for me to find more effective ways of accomplishing goals so that I don't have to work so hard to accomplish them.  I've built a highly successful career on that laziness, and I'm proud of that.  Is that bad?  I don't know.  What I do know is that both my laziness and my pride are essential components of who I am.  If you took those away, I wouldn't be me any more.

What about "fearful" and "restless"?  Well, I'm fearful on occasion.  For example, I'm fearful that climate change will destroy civilization.  This fear motivates me to overcome my laziness and moves me to act.  Restless?  That also motivates me.  If I give in to my laziness and sit on my duff for too long then I become restless and feel the need to do something like write blog posts.

All of these things are essential parts of me.  If you took them away, I wouldn't be me any more.

But I like being me.  Becoming the person I am has taken 54 years of work, sometimes very hard and painful work, and I'm generally pretty happy with the result so far.  This is not to say that there isn't room for improvement.  I'm still a work-in-progress, but even that on-going project is an essential part of being the person I have become.  I would be very reluctant to give that up.

Even my mortality is an essential part of who I am.  Railing against death like Lear against the storm is part of being human.  If you think about it, taking the prospect of heaven seriously means that saving someone's life is not a noble act.  You aren't saving their life, you are delaying their entry into heaven!  (Jehovah's Witnesses and Christian Scientists actually take this seriously!)

Accepting that death is the end removes the moral ambiguity from saving someone's life (which, if you think about it, is actually an oxymoron.  You can't save someone's life, you can only extend it.)  And this, too, is an essential part of being human.

Being human is fundamentally about struggling because being alive is fundamentally about struggling.  The key to living a good life is not to seek and end the struggle, but to find the right balance so that the struggle doesn't break you but sustains you instead.

So... maybe heaven is an eternity of having just the right amount of struggling, just the right amount of ignorance, just the right amount of laziness and pride and restlessness?  Well, yeah, maybe.  But this doesn't sound to me like what's on offer in Christian heaven.  In Christian heaven, ignorance and pride and laziness and fear and restlessness are unalloyed evils and so are banished forever.  So it's not just that I would get bored after a few trillion years of bliss and then be screwed for all eternity.  I would have to give up some essential parts of my identity on day one.

I suppose a Christian would say: yes, you're exactly right, in order to enter heaven you do have to give up some parts of your identity, specifically, you have to let go of sin.  But to me, the things that I would have to let go of don't feel like sins, they just feel like imperfections.  I don't want to let those go because my ongoing struggle against my imperfections and those of my fellow man is what gets me up in the morning.  If those went away, I honestly don't know what I would do with myself.

So while I can understand the appeal of a promise of eternal bliss, especially for someone who has not been as incredibly fortunate as I have to find the right balance of struggle in their lives, it still feels to me like a bad deal even on its own terms.  And if I'm right and it is a bad deal, then it's worth figuring this out before you get to heaven because once you get there it's too late.  You're screwed.  There is no way out.  It's not like buying into a time-share where you can just write off the loss, learn the lesson, and get on with your life.  Once you get to heaven, that is your life.  Forever.

Be very careful what you wish for.  Especially if the offer is non-refundable.

Wednesday, April 10, 2019

The Impossible Burger is going to change the world

I had heard about the soy-based Impossible Burger a long time ago but they are not yet widely available.  Burger King is launching a pilot program offering Impossible Whoppers (the original of which just happens to be my favorite fast-food burger) but they are only available in the midwest at the moment.  Happily, it turns out that a number of smaller restaurants are offering them where I live, and today I got to try one.

It's not as good as a regular burger.  It's better.  It really does taste like beef, but that description doesn't really do it justice.  Because it's made of soy, which is bland, they have to spice it up (literally) to make it have any flavor at all, and their secret recipe of eleventy-two herbs and spices (I'm guessing) is just incredibly tasty.  It's subtle.  The beefy flavor is the definitely center stage (courtesy of added heme), but it doesn't taste like beef that is straight out of the package.  It tastes like beef that has been lovingly seasoned by Thomas Keller to just the point where none of the additions stands out, but the whole is much, much greater than the sum of its parts.  A bit of thyme, a touch of sage, a hint of smokiness.

But the flavor is not the best part, it's the texture.  It not only tastes like beef, it looks and feels like beef, but without any gristle or stray bits of bone and tendon that you sometimes find in some less-than-highest-quality cuts.  Every bite is uniformly perfect, what you'd get if you hand trimmed the absolute finest prime sirloin you could find.

I think this product is going to change the world, not necessarily because it's healthier than beef (the jury is still out on that) but because it's so much more environmentally friendly to produce.  Beef production wreaks holy hell on the environment.  Offering people a greener alternative that doesn't require any compromise in flavor or texture, indeed improves on the original, is going to be huge.  The Impossible Burger is the Tesla Model S of meat.

Sunday, April 07, 2019

We interrupt this blog to bring you a little eureka moment

One of the reasons that my posting has been more sporadic that usual is that I have a few other balls in air at the moment.  One of these is an on-going lecture series about the history of science.  The next installment is on relativity, and in preparation for that I am reading a book called "Philosophy of Physics: Space and Time" by Tim Maudlin.  It has the single most lucid explanation of relativity that I have ever encountered, which can be boiled down to a pithy slogan:
Clocks don't measure time!
What clocks actually measure is the space-time interval between events on the clock's world-line.  That turns out to reduce to what we call "time" if you and the clock are not moving relative to each other.  But if you and the clock are moving relative to each other, then things get weird because, well, clocks don't measure time.  In fact, time is not even a well-defined concept when things are moving relative to each other!

Two surprising consequences of this: first, the speed of light is not constant.  In fact, "the speed of light" is not even a well-defined concept because time is not a well-defined concept, and speed is defined in terms of time.  (In fact, "the speed of X" is not a well-defined concept for any X, because, well, you know.)

(What is true is that the measuring the "speed" of light will give you the same result no matter what reference frame you're in.  But that turns out to be a consequence of the fact that clocks measure space-time intervals rather than time.  It is not, as is often taught, the foundational principle of relativity.  Einstein himself got this wrong.)

The second surprising consequence is that the most common resolution of the "twin paradox" is mistaken.  Maudlin quotes Feynman as the prototypical example:
This is called a “paradox” only by people who believe that the principle of relativity means that that all motion is relative; they say “Heh, heh, heh, from the point of view of Paul can’t we say that Peter was moving and should therefore appear to age more slowly? By symmetry, the only possible result is that both should be the same age when they meet.” But in order for them to come back together and make the comparison Paul must either stop at the end of the trip and make a comparison of clocks, or, more simply, he has to come back, and the one who comes back must be the man who was moving, and he knows this, because he had to turn around. When he turned around, all kinds of things happened in his space-ship—the rockets went off, things jammed up against one wall, and so on—while Peter felt nothing. 
So the way to state the rule is that the man who has felt the accelerations, who has seen things fall against the walls. and so on, is the one who would be the younger; that is the difference between them in an absolute sense, and it is certainly correct.
Maudlin then minces no words:
Everything in this "explanation" is wrong.
That sort of clarity is rare.

(It's actually easy to see that any explanation in terms of acceleration must be wrong because it is easy to set up a "twin paradox" that involves no accelerations: use three clocks all moving in inertial trajectories along the same line.  Clock A starts to the left of clock B and is moving to the right (relative to B).  Clock C starts to the right of clock B and is moving to the left (relative to B).  The initial positions are such that A will be co-located with B before it is co-located with C.  When A meets B, A is set to the time shown on B.  Then, when A meets C, C is set to the time shown on A.  When C meets B, the reading on C will be less than the reading on B despite the fact that none of the clocks have undergone any acceleration.)

Anyway, I thought this was cool and so I thought I'd take a moment to share it.

Secularity and teleology

1.  Introduction

In a previous post I advanced the hypothesis that the seemingly irreconcilable divide between religious and secular outlooks on life can be traced back to whether one chooses to begin one's philosophical inquiries with purpose or mechanism, i.e. whether one accepts teleology, the idea that our conscious experiences are indicative of some kind of purpose, as an axiom.  Jimmy Weiss responded to that (and also to some other points I raised) and here I want to respond to Jimmy.
I wonder if the reason Ron perceives an inordinate preoccupation with teleology among the faithful, is because he is accustomed to making so little of it?
I want to clarify that my hypothesis is emphatically not that the faithful have an "inordinate preoccupation" with teleology, only that they ask the question, "What is the purpose of subjective experience" before they ask the question "what is the mechanism behind subjective experience", whereas secular people reverse the order.  That's all.  The hypothesis is that both sides actually find answers to the respective question they started with, so that by the time they return to the other question they have already built up an intellectual framework into which the answer to the second question must fit.  So by the time a religious person returns to the question of mechanism they already know why they are here (or at least they think they do): God created them.  And any theory of mechanism that is inconsistent with that "fact" cannot possibly be true.  It would just make no sense.

Likewise, by the time a secular person returns to the question of purpose, they already know how their subjective experience works (or at least they think they do): subjective experience is an "emergent property" of brains, which were built by evolution.  Any theory of purpose that is inconsistent with that "fact" cannot possibly be true.  It would just make no sense.

And so the two sides are at loggerheads, and each side thinks the other side is populated by either morally rudderless heathens (in the case of the first group) or knuckle-dragging morons (in the case of the second).

It's just a hypothesis.  But it seems to fit the observed data.

If you're a secularist reading this, and you think this is a plausible hypothesis, then one of the practical consequences of this is that we could dramatically improve the effectiveness of our marketing if we had a better story to tell about teleology.  A lot of people yearn for purpose, and "life's a bitch and then you die, and that's just the way it is" is not a very attractive message.

2.  Why I reject Jimmy's wager

One of the interesting (to me) things about Jimmy Weiss's theology is that he is explicitly willing to admit that he could be wrong.  In our previous discussion on Reddit he put the odds at 5%, which is pretty substantial.  His argument for believing in God is not that God is a slam-dunk, but that it makes sense to believe in Him from a game-theoretical point of view: God promises an infinite reward in exchange for belief, and so if you crunch the "numbers" (I put numbers in scare quotes because infinity is not actually a number) it turns out that expected value of belief is infinite even if the odds of God actually existing are finite.

I think this argument is wrong on technical grounds, but one of the things I've learned is that geeking out about these things is very rarely effective.  Instead, the reason that Jimmy's wager doesn't work for me is that I believe that an infinite reward is fundamentally incompatible with human nature.  We are living creatures.  Being mortal is woven deep into the fabric of our being.  We're born, we mature, we have children, we raise them, and then we get out of the way and let them have their turn in the great circle of life.

The appeal of an infinite afterlife depends a lot, I think, on a failure to grasp just how big infinity is.  To paraphrase Douglas Adams, infinity is big.  Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is.  I mean, you may think it's a long time waiting for Christmas morning to arrive, but that's just peanuts compared to infinity.  With infinite time you can read every book in the Library of Babel.  If you put an upper bound -- any upper bound -- on how long a book you're willing to read (100 million pages, say) you can read every one of those books an infinite number of times.  And if you spend even a little time browsing the Library of Babel you will see that reading most of those books is not going to be a lot of fun.

You can read every book, watch every movie, have every conversation that it is possible to have, see every sight, taste every taste, smell every smell, and do all of those things 100 millions times and still not put a dent in infinity.

I think I would be bored out of my mind after a mere trillion years.  I would yearn for oblivion.

So God's reward doesn't sound like a reward to me at all.  In fact, I can hardly imagine a worse fate than to be immortal.  This is not to say that I wouldn't like to live longer than I will.  Threescore and ten is a little shorter than I'd like.  But I'll take it over infinity.

3.  Towards a secular teleology

Here I'd like to address the second part of Jimmy's question, the "making so little of it" bit.  I don't make "so little" of it.  I want life to have a purpose.  But just because I'm not given a purpose by God doesn't mean I don't or can't have a purpose.  It's possible that I am given a purpose by nature, or it's possible that I can create my own purpose.  I think both of these are actually the case, and I think that idea-ism can serve as a basis not just for a secular morality but also for a secular teleology (for those who care about that sort of thing).  That could (and probably should) be its own post, but I'll just say this for now: I find it very fulfilling to learn about other people's ideas, and to come up with and promulgate ideas of my own (that's one of the reasons I write this blog).  But more than that, I think it's constructive.  I think it makes the world, at least in a small way, a better place.  If I write something that someone reads and enjoys, for whatever reason, then I've increased the net goodness in the world, and that makes me happy (that's why I like getting feedback).  There's also the chance that my words could outlive my body and give me a kind of immortality, one that won't actually turn into torture.

4.  Geeking out about the excluded middle

I don't quite understand why this is turning out to be such a big deal, but Jimmy keeps beating on the excluded middle so I feel the need to beat back, because I really do reject this:
Donald Trump either is, or he is not, a scoundrel.  One or the other must be true, if anything particular is meant by the word “scoundrel”.
The word "scoundrel" definitely has a meaning (it means "a dishonest or unscrupulous person") but that doesn't mean that the statement "X is a scoundrel" is either true or false.  Scoundrel-ness is a continuum, not a dichotomy (though Donald Trump seems to be to be a rather extreme outlier on the scoundrelly side of the scale, so perhaps that wasn't the best example).  But there are lots and lots of things like this where the truth or falseness of a statement doesn't turn on opinion or subjective experience, but rather on the lack of sharp dividing line (e.g. "A million dollars is a lot of money") or a counterfactual ("If the Russians had not meddled, Hillary would have won") or the lack of an objective referent ("Batman would beat Superman").

And, to give an example that I think falls afoul of more than one of these and is actually relevant to this discussion: "God is good."  Maybe I'll make that the topic of my next post.


It is worth noting that, despite the fact that all of the above is part of an on-going discussion with a young-earth creationist, absolutely none of it had anything to do with the age of the earth.

Saturday, April 06, 2019

Why you should care about what a YEC thinks

I've had a number of people contact me off-line to tell me that they, like Don Geddis, are not at all interested in this whole YEC thing.  This response was typical:
I am [a] European, and I am sure you, at least from a general and abstract point of view, understand that the USA are not the World, and that some of the things  that seems so important to you, are just the construct of what the USA culture, politics, history etc ... but are just, to people from other backgrounds one of the many USA weirdness (as I am sure there are European weirdness, Swedish weirdness etc.). 
IMVHO, YEC and the need to argue with them, is one of those.
I actually didn't realize until I did some research prompted by the above correspondence that YEC is indeed a uniquely American phenomenon.  I was under the impression that it was world-wide, and in fact there are a lot of non-American non-Christian creationists in general (most Muslims are OECs).  But young earth creationism does appear to be uniquely American (and Christian).  I didn't know that.

But all this is not about YEC per se.  This is an exercise in trying to find common ground with someone with whom I vehemently disagree, and to see if I can learn some lessons from the experience that generalize to other domains.  I ended up partnering with a YEC in part because that just happened to be the kind of person I could find who was willing to engage with me.  I would have happily done this with a Muslim or a Mormon or a Jehovah's Witness (I've actually had a few conversations with Witnesses and found them to be quite knowledgable and intellectually honest.  But it's a very small sample size.) but it turns out to be really hard to find people willing to engage in this sort of thing, and even fewer who are willing to be intellectually honest about it.  (If you want to volunteer, please let me know!)

I happen to think that it's a good thing that I'm doing this with a YEC in part because the scientific evidence against YEC is so overwhelming.  Figuring out how an intellectually honest person can sustain such a belief is, I think, interesting just in and of itself.  It is not a simple matter of "cognitive dissonance" as Don Geddis has glibly claimed.  Cognitive dissonance simply means "the state of having inconsistent thoughts, beliefs, or attitudes."  In other words, CD is just a label for the phenomenon, it's not an explanation.

Whoever you are, American or European, religious or not, the world is full of people with whom you will vehemently disagree about something.  Responding to that by retreating into enclaves of like-minded people is not going to produce good outcomes in the long run.  This planet is only so big, and at some point you are almost certainly going to have to interact in some way with someone with whom you vehemently disagree.  The world will be a better place if more people learn how to do it without resorting to violence.  Even if you don't have to deal with Islamic State in your back yard, there could be other religious fundamentalists closer to home.

If you happen to be religious, you might want to follow this exercise (or even engage in it yourself) because it turns out that atheism is on the rise in the U.S.  Atheists now outnumber evangelicals -- narrowly at the moment, but the trend is solidly  in our favor.  (If you're a social conservative, which is strongly correlated with being evangelical, things are looking particularly grim for you in the long run.)  You might want to get to know us better, and in particular, find out why we "choose to reject God's grace", and why we nevertheless do not in fact rape and pillage despite having no apparent moral compass.

Finally, if you're a Christian but not a YEC (I'm looking at you, Publius) then you have a theological difference that you might want to try to resolve.  At the very least, you differ in the interpretation of Genesis.  Are you sure you understand YEC hermeneutics (never mind the science) well enough to definitively rule it out as a possibility?  Because if you can't, then it's possible that you're making a mistake that will impact your prospects of salvation.

Just sayin'.

Friday, April 05, 2019

[Crickets chirping]

At the bottom of each Rondam Ramblings post is a set of four "reaction boxes".  Three of them are labelled "Right on", "Bogus", and "Thought-provoking".  These are there so that readers can weigh in with an opinion about the post with a minimum of fuss.  Of course, readers can leave comments too, but if anyone feels like they don't really have anything substantive enough to say in a comment, or if they just don't want to be bothered, they can express a point of view with a simple click.

There's a fourth reaction box labelled "Read it".  That's there for people who don't have an opinion one way or the other, but still want to let me know that they read the piece and appreciated the effort that went into writing it.  Comments, and the tallies on those reaction boxes, are the only compensation I get for writing this blog, and it's enough.  This blog is a hobby, and just knowing that someone is reading it and finds it worthwhile is enough to keep me going.  Not everything I post garners comments, but it has been a very long time since I've posted something that absolutely no one responded to, not even by clicking on "read it".

Well, the last two entries I posted, the ones about my adventures in YEC-land, have gotten zero reactions, and the only substantive comment they garnered was from Don Geddis, who went out of his way to tell me that he didn't really care.  Apparently, he wasn't the only one, and that's kind of depressing.  Writing those posts took a lot of effort, and I have a hard time believing that they are really the most uninteresting thing I've posted since I added reaction boxes to the site.

Anyway, that's one reason it is taking me a long time to post a response to Jimmy Weiss's latest posts.  The lack of encouragement on the first installment has been a little deflating.  (I'm also dealing with some personal matters and private correspondence.)  If you really don't care, well, so be it (though in that case I would appreciate some feedback on what you would like me to write about.  There are 122 of you who have subscribed to this blog, surely there's something you're interested in seeing here?)  But if you do, a simple click can provide a lot of encouragement.

Sunday, March 31, 2019

Can a Scientist find common ground with a young-earth creationist?

This is a response to this post by Jimmy Weiss.  For more background, see this.

Let me start with the positive: I am grateful to Jimmy for taking the time to write his article.  I asked him to do it because we had been having a very cordial, constructive, and, at least for me, instructive discussion on Reddit and I wanted to be able to share that with a wider audience.

Second, one of the things that impressed me about Jimmy was his intellectual honesty.  In my experience, many Christians when confronted with some of the more odious parts of the Bible (particularly the Old Testament) become defensive, or even get offended.  Jimmy didn't.  He tackled all of my questions head-on without ever flinching.  Needless to say I was not much persuaded by his answers, but just the fact that he was willing and able to provide them at all impressed me.  I actually learned a lot.

Third, I think we really do have some common ground.  Jimmy is willing to take math and science pretty seriously, and I (I like to think) am willing to concede when my position is on less-than-rock-solid ground.  For example, I believe that life began through a process of abiogenesis despite the fact that science has not yet figured out how it happened, or even how it could have happened.  There's a lot of (plausible, at least to me) speculation about how it might have happened but no one has yet been able to convincingly fill in the details.  Nonetheless, I believe very strongly that science will eventually fill in the details, but at this point that is an article of faith.  Yes, science has a pretty good track record of filling in details (which is the basis of my faith) but as investment advisors perennially remind us: past performance is not a guarantee of future results.

Unfortunately, that's kind of where my optimism ends with regards to Jimmy's article.  He starts out with his own speculation about our common ground:
I believe that Ron and I are agreed on all but one of these preconditions.  As I understand them, in order for us to be able to make any sense at all of the universe, we have to accept a few basic axioms.  The first is that the laws of logic are absolutely true.  These laws include: 
(A) The Law of Identity, which states that something is what it is, and whatever exists must have a specific nature. 
(B) The Law of Non-Contradiction, which states that something cannot be itself and not itself at the same time, in the same way, and in the same sense. 
(C) The Law of Excluded Middle, which states that a statement is either true or false, with no third option.
He doesn't say which of the three is the one I'm presumed not to agree with, but in fact I don't agree with any of those three.  I have a pretty nuanced view of ontology, so I don't accept the continuity of identity in general, and certainly not as an axiom.  (I have no idea how Jimmy got the idea that I would accept this.  I pointed him to the 31 Flavors article several times, and we never actually discussed this "law of identity".)

His formulation of the "law of non-contradiction" gets into the same muddy waters as continuity of identity. I certainly accept something that could be called a "law of non-contradiction", but I wouldn't characterize it the way he does in terms of "things being themselves".  I would simply say that if you find yourself having concluded that P is true and NOT P is also true, then you've done something wrong.

With regards to the law of the excluded middle, there are clearly statements for which this is not true, e.g. "Donald Trump is a scoundrel" or "Polar bears are beautiful." Even seemingly straightforward statements like "Socrates is a man" can be problematic. That statement was (probably) true at one time, but it isn't true any more because Socrates is dead.

So I'm going to just ignore all that and take my own stab at a starting point that I think (hope?) Jimmy (and everyone else) will agree with.

I hereby propose the following hypothesis (or perhaps I should say "I hold this truth to be self-evident"):
The most reliable information you can possibly have about reality is your own subjective experiences.
It seems self-evident to me because your own subjective experience is the only information that you actually have direct access to.  I dub this Ron's Law of Reality or RLR just so we can refer to it.  Note that by "subjective experience" I include things like the subjective experience of reading a book or having a conversation with someone or seeing someone perform a scientific experiment, or even performing one yourself.

I don't know if the RLR is actually self-evident, but just in case it isn't let me advance an argument for it: think about what it would be like to receive reliable information about reality that was not part of your subjective experience.  Somehow you would find yourself knowing something, but you would have no idea how you came to know it.  Not only that, but you would not even be aware that you possessed this knowledge, because that awareness itself would be part of your subjective experience.  That knowledge and the means by which it was acquired would have to somehow be completely hidden from your conscious self.

Now, there are some things that are kinda sorta like that.  For example, your heart beats whether or not you are aware of it, and so you might say that you "have information" about how to make your heart beat even though you are completely unaware of what that information is or how you got it.  I would say in that case that this information is not resident in "you", it is resident in your body, and your body is not you.  The you to which the RLR refers is the thought processes inside your brain, or, if you prefer, your soul.  (In that regard you (pun intended) could consider the RLR to be a tautology because I've simply defined "you" as "that which has subjective experiences.")

Assuming you're still with me on that, I think we can go a little further before we really start to diverge.  There are some aspects of subjective experience that are common to the vast majority of human beings.  For example, our subjective experience divides up into two regimes, which we call "being awake" and "dreaming".  "Being awake" is more coherent than "dreaming".  In both regimes we perceive the existence of other agents with which we interact, but the cast of characters across episodes of "being awake" tends to change more slowly than it does between episodes of "dreaming".  Furthermore, "being awake" is subject to more uniform laws and constraints than "dreaming".  When we are awake there is a lot of regularity and limitations: we can't fly unassisted.  The sun and planets move in predictable patterns.  And, moreover, everyone agrees on a vast range of these experiences while "being awake" whereas everyone's subjective experience while "dreaming" seems to diverge.  Different people have different dreams, but, at least to a certain extent, we all seem to have very similar subjective experiences while "being awake" (though even here there are divergences, such as the question of whether or not something tastes good).

All this is, I hope, uncontroversial, perhaps even to the point of tiresomely belaboring the obvious.  But bear with me, there is a reason for this, because what I am going to say next is going to be far less obvious.  The divergence between science and religion occurs, I believe, in what happens next: having lived for a while and accumulated some subjective experiences, a human being naturally comes to ask some Deep Questions.  In particular, I think there are two different Deep Questions that people naturally ask.  They are both perfectly good questions, but which one you choose to ask first has a profound impact on your thought processes from that point on.

The first Deep Question is: What are the laws that govern my subjective experiences? (And in particular, what are the laws that govern the regularities of Being Awake)?

The second Deep Question is: What is the purpose of my having subjective experiences in the first place?

My thesis is that the first question leads to science, the second to religion.

(N.B. I am using the word "purpose" here to refer to what philosophers call teleology.  To restate my thesis in more technical terms, the difference between science and religion is that religion accepts teleology as an axiom (or at least as a possibility worth putting considerable effort into pursuing) and science doesn't.  I'm sure this is not an original idea, but it doesn't seem to be very widely appreciated either.)

I am a Scientist (which I capitalize to distinguish it from being a lower-case scientist, who is someone who does science for a living.  An upper-case Scientist is someone who accepts science as a reliable process for learning about reality) so I choose (or perhaps chose in the dim and distant past) to ask the first question.  But there's nothing wrong with asking the second question instead.  It's a perfectly respectable question.  And if you choose to ask that instead it leads down a very different road.

For starters, in order to ask what the purpose of having subjective experience is you have to accept as an axiom that it is at least possible for there to be such a purpose, otherwise the question makes no sense.  Likewise, if you are going to ask the first question then you have to accept as an axiom that it is at least possible that there are laws that govern the regularities of subjective experience (at least those parts that have regularities).

If you start with the first question, then you discover that there are laws that govern a lot of our subjective experiences, at least the wakeful ones.  Moreover, these laws are at root quite simple and elegant and have very wide-ranging applicability.  The heavens are not, as the ancients once believed, fundamentally different from the earth.  The stars are made from the same stuff that we are and operate according to the same laws.  It all hangs together quite nicely, and by the time you learn enough of it you get to the point where if someone proposes something to you that doesn't fit the laws of physics you reject it out of hand because it just doesn't make sense at this point that some random thing should violate the laws of physics.


If you start with the second question, and hence the presumption that it is at least possible for there to be a purpose to subjective experience, then Jimmy Weiss's arguments start to make a lot more sense.  That argument goes something like this (and Jimmy, please correct me if I get part of this badly wrong):

The subjective experiences we have while we are awake are very powerful evidence that there exists some kind of objective reality which we call the universe (on this religion and science mostly agree).  The natural next question to ask, if you're on the teleology track, is: what is the role of the universe in the purpose of our subjective experience (which is, keep in mind, what we are endeavoring to discover)?  And the natural answer is that the universe exists for the purpose of allowing us to exist so that we can have subjective experiences.  In other words, it was made for us.

(Or something like that.)

By the time both camps get around to asking Where did the universe come from? they have already diverged past the point of reconciliation.  Science gets you to the Big Bang, at which point it kind of throws up its hands (at least for now) and says, "We just don't know."  But more than that, science says, "It's OK that we don't know.  Not knowing is a perfectly normal state of affairs.  We'll figure it out some day.  In the meantime, don't worry about it."

But if you're on the teleology track, not knowing how the universe came about is not OK because it leaves a crucial question unanswered: if the universe was made for us, who (or what) made it?  A universe made for us but by nothing makes no sense.  Remember, we're assuming teleology (or at least the possibility) as an axiom here.  It might be possible that the universe was created by nothing, but that is (on the teleological view) the kind of extraordinary claim that requires extraordinary evidence, and ignorance doesn't qualify.  We have to keep looking for the answer.  And, happily for us, there is an answer: the universe was made by an exceptionally powerful, potentially ineffable entity, i.e. a deity, who made it for us, and hence cares about us.

And it's all downhill from there.  (Note that I don't mean that to be pejorative, though I did mean it to be slightly humorous.  What I mean is that once you get this far, the remaining arguments are pretty straightforward by comparison.)

One of the things that atheists often ask about religious people, and particularly about YEC's is, "How can they possibly believe that crazy shit?"  Because some of the things that YECs believe make absolutely no sense whatsoever in light of modern scientific knowledge.  The difference in the age of the universe between the YEC view and the modern scientific view is six or seven orders of magnitude.  That's the equivalent of estimating the distance from Los Angeles to New York as a couple of millimeters.  It's simply ridiculous.

Well, the way they get to believe "this crazy shit" is (I claim) by starting with the teleological question and taking it very seriously.  For a scientist, an answer that is wildly at odds with the data makes no sense.  But for a YEC, an answer that denies the existence of purpose (or even merely throws in the towel) makes no sense.  So... the universe must have been created by a deity for us, and who therefore cares about us.  How do we make progress from there?  Well, it seems reasonable that if such a deity existed, it would have made arrangements (because it cares) for us to make further progress, and lo and behold there is this book that purports to be exactly that (that is, the means for making further progress).

On this view, the Bible is not mythology, it's the fulfillment of a prediction made by our theory!  And it provides a very satisfying answer to the teleological question: our purpose is to reconnect with  this deity that created us!  And, as a bonus, that reconnection will right all of the wrongs that have happened in this life, so not only do we get an answer to the Big Question, we also get an eternal and infinite reward!  What reasonable person could possibly argue with that?

And this is the reason I respect Jimmy Weiss.  He really takes this seriously.  If the Bible really is the Word of God, then it must be the case that the universe was created in six days, because that's what the Bible says.  I have a lot more respect for that than I do for self-identified Christians who cherry-pick the Bible.

It's no crazier on its face than accepting that we don't really exist, that objective reality is an illusion, because that's what Schroedinger's equation says.  It is in this regard, in our willingness to unflinchingly accept the logical consequences of our core beliefs even when they turn out to be deeply unintuitive, that I consider myself and Jimmy Weiss to be kindred spirits despite the fact that we end up in very different places at the end.

An atheist and a YEC walk into a bar...

Enough politics.  Let's talk about religion.

Ever since I was a kid growing up in the deep south I have been mystified by how people can believe in God.  Note that I didn't say "why people believe in God", because that's a different question.  I think I understand the why (it helps people deal with existential angst); it really is the how that I have trouble understanding.  To me, it has always been self-evident that the Bible is a work of mythology, and so for a long time I was firmly of the opinion that the only way that one could sustain a belief in God was through ignorance.  This belief was reinforced by the people I tended to hang out with, mostly other atheists, who spent a lot of time and effort promoting rational arguments that religion is false.  (A commonly held view in the atheist community seems to be that the scourge of religion persists on this earth simply because atheists have been insufficiently diligent in spreading the seeds of enlightenment.)

Ironically, this theory is contradicted by data.  A lot of atheists seem to think that religion and education are universally anti-correlated, but this turns out to be false.  There is some truth to it, but one of the many noteworthy exceptions is American Christians.  (Jews and Hindus also tend to have significantly better than average educations.)  It was also contradicted by my personal experience.  Like any good atheist, I spent a fair amount of time arguing with religious people, and over the years I noticed two things: first, my arguments never seemed to persuade anyone (though it was not uncommon for me to offend people by reading certain Bible verses to them).  And second, a lot of the people I was arguing with were actually very smart and somehow managed to sustain their beliefs despite being well aware of all of the apparent absurdity.

This matters.  People's beliefs about religion vs. science sometimes get translated into policy, and getting it wrong can have grave consequences.  Accordingly, I think it's important to develop an understanding of the mindset that leads people to believe differently than you do rather than just dismiss them as ignorant knuckle-draggers (or, if you're religious, as incorrigible hedonists lacking a moral compass).  One of two things has to happen: either you'll learn something that will help you focus your own message and make it more effective, or you might come to realize that you were actually wrong about something.  Either way, that feels like progress, so over the past few years I've spent quite a bit of time hanging out with and talking not only to religious people, but also to believers of extreme views that seem completely crazy to me, including lunar landing denialists, flat-earthers, and creationists.  It's been a very interesting experience.  I've been fairly impressed with the sophistication of their arguments, even though, of course, I vehemently disagree with them.  It has forced me to think deeply about the foundations of my own beliefs, because although (say) a flat-earther's arguments seem absurd to me, refuting them turns out not to be quite as easy as you might think.

The fundamental problem is that today's world is much too complicated for an individual to figure out everything on their own, so you have no choice but to trust somebody.  No one has the resources to obtain first-hand evidence for everything they believe.  If you're an atheist you (almost certainly) adhere to certain beliefs because of something you read somewhere rather than (say) an experiment that you personally did, and that means that you have to trust that the author is not mistaken or trying to deceive you.  Now, there may be a sound reason to trust the author of (say) a scientific paper, but most people who put their trust in science don't actually give that a lot of thought.  They just hew to formulas like: if it is published in a peer-reviewed journal it's probably true (and vice versa).  And they will continue to believe this even in the face of evidence to the contrary published in a peer-reviewed journal!

There is a sort of social hierarchy of respectability of the sorts of trust that people choose to adopt.  At one extreme are scientists and members of the clergy of established religions like Christianity and Islam.  At the other extreme are the flat-earthers, lunar-landing denialists, alien abductionists, and Bigfoot hunters.  Somewhere in between are the young-earth creationists (YECs) who believe that the Bible is the literal and inerrant Word of God, and that therefore the world was created in six 24-hour days about six thousand years ago, that Noah's ark was real, and that Charles Darwin is the spawn of Satan.  (FYI, that link is to an article about Ben Carson, the famous neurosurgeon, currently serving as Secretary of Housing and Urban Development in the Trump Administration.  Carson is a Seventh Day Adventist, and hence a YEC.  And he is quoted as saying that Darwin's evolutionary theory "was encouraged by the adversary," i.e. the devil.  So "spawn of Satan" is really not much of an exaggeration here.)

These groups are minorities whose identities are defined by unfashionable beliefs, and so their adherents often feel beleaguered by modern society.  As a consequence, it's not easy to get them to talk to someone outside of their group.  They often view outsiders as the enemy.  But I've recently had the rare opportunity to have an extensive discussion with a YEC who was willing to engage with surprising confidence and intellectual honesty.  Over the past few weeks we've had what is quite possibly the longest civil exchange between and atheist and a YEC in the history of the world.  The thread started to get out of hand, so we decided to reboot the discussion here because Blogger is a better venue for extensive discussion than Reddit.  My correspondent's name is Jimmy Weiss, and his opening salvo is here.  The opportunity to have this kind of discussion with a knowledgable YEC is rare, and I am grateful to him for being willing to put himself out there in this way.  The differences between YEC and established science are quite stark, and it is not an easy position to defend in today's world.  Jimmy does quite an admirable job.

This introduction turned out to be quite a bit longer than I intended, so I will put my actual response to Jimmy in a separate post later today.

Tuesday, March 26, 2019

Something doesn't smell right about the Mueller report

Let me confess up front to having an enormous bias here: more than just about anything else in the world, I want to see Donald Trump go down in screaming flames, if for no other reason than that he is a colossal asshole and I hate seeing assholes win.  I also have more than a few policy disagreements with him, so even if he wasn't such an odious louse, I would still want him to go down in screaming flames.  And of course I am not alone in this.  A lot of people were hoping the Mueller report would be the beginning of Trump's undoing.  So I don't know how much of what I'm about to say is colored by my disappointment at how events have unravelled.  And yet... something's not right here.

For starters, our process for uncovering wrongdoing by the president is deeply flawed.  Despite the appearance that Robert Mueller was being objective and patriotic, the fact of the matter is that he was, notwithstanding Trump's occasional tweets to the contrary, a Republican, and so he could have a partisan bias.  There's no check-and-balance on Mueller.  If he decides to put his thumb on the scales in favor of the president there's no one who is going to stop him.  But even if Mueller is exactly what he appears to be, a professional doing his job fairly, objectively, and competently, there is still the problem that his work is being filtered by William Barr.  Remember, we don't know what the Mueller report says.  All we know is what William Barr says it says, and we know that Barr is strongly biased in favor of the president.

But even if Barr is being completely honest about the contents of the Mueller report, the process here is still deeply flawed.  If you want to uncover someone's wrong-doing, you don't give prosecutorial veto power to someone who was appointed by and is beholden to (indeed, works for) the subject of the investigation.  Congress is supposed to be the governmental body that keeps the president in check, but that only has a chance of working if Congress has some way of learning the actual underlying facts unfiltered by people with obvious conflicts of interest.  So there's that.

But even more troubling to me is that there's just something very fishy about the way things have gone down in the last two weeks.  Mueller seemed to be on a roll, racking up indictments and convictions, and closing in on the president's inner circle.  The entire time, Trump was acting like a cornered animal, tweeting non-stop criticism of Mueller, accusing him of hunting witches and being a (gasp!) Democrat (there is no more serious insult in the Republican lexicon).  I've long since lost count of the number of times Trump called for the investigation to be shut down.  Hell, he fired James Comey in a failed attempt to shut the investigation down!  And then, all of a sudden, before Mueller released his report, Trump suddenly changed his tune.  On March 20, Trump suddenly stopped the criticism and said that the report should be made public, that people should see it.  That was two days before Mueller delivered the report which -- surprise, surprise! -- "exonerated" Trump.

Why would Trump suddenly change his tune so radically in advance of the report?  I can think of only one possible explanation: he knew the fix was in.  Just as I can think of only one possible explanation for his announcement during the campaign, on June 7, 2016, that he was going to give a "major speech ... discussing all of the things that have taken place with the Clintons...": he knew about the infamous Trump Tower meeting that was scheduled to take place on June 9, and he knew (or at least he thought he knew) that that meeting was supposed to yield dirt on Hillary.  If that's not collusion, I don't know what is.

To quote Baby Herman, notwithstanding Trump's claims of total vindication (which even William Barr doesn't actually agree with), the whole thing stinks like yesterday's diapers.

And that's the real problem here.  The country is divided.  One way or another, we really need to know the truth, and having a report about possible wrongdoing by the president released only after the president has had a chance to "review it for accuracy" is not going to give the skeptics a lot of confidence that we're getting the truth.

Our legal system is supposed to be, for better or worse, adversarial.  It doesn't work if the prosecutor is working for the accused.

Tuesday, March 12, 2019

There and Back Again

You may have noticed that the Ramblings have been quiet for a while.  It has been six weeks since my last post, which I'm pretty sure is the longest hiatus I've had since I first started writing this blog over fifteen years ago.  There have been two reasons for this.  First, I've been on the road.  Nancy and I took a two-month-long trip starting in Singapore, cruising across the Indian ocean to Cape Town, then going on Safaris in South Africa, Rwanda, and the Maasai Mara in Kenya.  It was pretty epic.

There was a time when I would have "live blogged" the trip with regular travelogues while away, but in this day and age I have come to question the wisdom of overtly advertising the fact that we are away from home.  An acquaintance of mine had their house robbed shortly before we left and apparently it sucks pretty badly.  All the evidence indicates that the perpetrators were professionals who knew they were away.  So sorry about that, but that seems to be the world we live in now.  If there's enough interest I might go back and write some travel retrospectives.  If you'd be interested in reading those, click on the "Right On!" reaction button below, or better yet, leave a comment.

The second reason I haven't been writing is that I've been engaged in a fascinating exchange with a young-earth creationist over on Reddit.  I think we may have set a record for the longest ever discussion between and atheist and a YEC on Reddit, possibly in the history of humanity.  I'll be writing more about that later, but what spare time I had for thinking about non-travel-related things on the trip went into that discussion instead of blogging.  (It's actually very hard to write quality blog posts without a good internet connection to look things up on.)

We flew back from Nairobi via Dubai -- 24 hours flying and a 12-hour time zone change -- so I'm still a little jet-lagged.  But in the meantime here are a few photos I took on the trip.

The leopard and her cub were at Sabi Sands in South Africa.  The gorilla was in Volcanos national park in Rwanda.  Rwanda turns out to be one of the best-kept secrets in Africa.  The extent to which that country has gotten its act together since the 1994 genocide is truly remarkable.  I would go back there in a heartbeat.

One of the highlights of the trip was the opportunity to get a much closer look than I ever had before at what African village life really looks like on the inside.  The lodge that we stayed at has developed a cooperative relationship with the nearby village.  The lodge uses some of its proceeds to help improve the lives of the villagers and in exchange guests at the lodge can come tour the village, meet the people who live there, and take photos without getting hit up for money or feeling like creepy voyeurs.  I'd heard stories of village life before, but this was my first chance to actually see it up close and personal.

This is Maria:

She is 50 years old.  She owns two cows, which makes her relatively wealthy by local standards.  Nonetheless, she has to walk 30 minutes each way to fetch water in a 20 liter jerrycan every day.

This is Maria's bedroom:

And this is a store that she opened in the village with the help of about $20 worth of capital from the lodge to buy her initial inventory:

(That's not Maria minding the store, that is one of her employees.)

That's what a startup looks like in rural Rwanda.

Monday, January 21, 2019

Are you a Turing Machine?

A few days ago, regular commenter Publius drew my attention to a paper by a fellow named Selim G. Akl entitled "The Myth of Universal Computation."  In it Akl claims to exhibit functions that are computable, but not by a Turing machine.

If this claim were to pan out it should be big news because Turing machines are supposed to be "universal", that is, capable of computing any computable function.  The universality of Turing machines has been the bedrock of computer science for eighty years.  And yet you have almost certainly never heard of Selim G. Akl.

IMHO the obscurity in which Akl's work has languished is well-deserved, and I'm more than a little inclined to let these sleeping bogons lie.  But if Publius is citing Akl that means that this is probably making the rounds in the Christian-industrial network and so someone is going to have to debunk it sooner or later.  It's a dirty job, but I guess somebody's gotta do it, so it might as well be me.

It's a lot easier to talk about computability nowadays than it was in Turing's time because computing is now ubiquitous and hence familiar.  Modern consumers have some intuitions about what it means for one computer to be "more powerful" than another, and some idea of what makes one computer more powerful than another: More memory.  Bigger disk.  Faster processor.

What about having "Intel inside"?  Is there anything an Intel processor can do that (say) an AMD processor can't?  It turns out the answer depends on what you mean by "do".  There is nothing that an Intel processor can display on a screen that an AMD (or any other brand of) processor can't.  An Intel processor might be faster, and that might matter to you, but if you disregard time, all processors are essentially equivalent, and their limitations are defined almost entirely by how much memory they have.

One the other hand, if you don't ignore time then the details of the processor architecture do matter.  Some processors, for example, have more than one "core", the part of the processor that actually does the work.  If a processor has only one core then it can only do one thing at once.  It can give the appearance that it is doing multiple things simultaneously by switching rapidly back and forth between multiple tasks, but a processor with multiple cores can do multiple things literally at the same time, with concomitant performance improvements not just from the parallelism but also from the elimination of the switching overhead.  Similarly, if you care about security, some processors provide better protections than others against programs interfering with each other, or doing things like sending your banking credentials to Romanian hackers.

What if we ignored all of these practical considerations and considered only what a computer could do in principle if we could make it as powerful as we wanted?  Such a super-duper computer (SDC) would have two characteristics: it would run ridiculously fast, and it would have a ridiculous amount of memory.  How fast?  How much?  You name it.  Yottahertz.  Ziggybytes.  The only constraint, if we want this computer to be even remotely plausible as a model of anything that could exist in the real world, is that these numbers be finite.  They can be unbounded, that is, we need not commit ourselves to any particular numbers, but they can't be infinite.

As an aside, we actually can make some plausible estimates of upper bounds for these numbers in our universe.  For example, barring some major breakthrough in our understanding of physics, a real computer could never have a clock rate faster than the Planck frequency of 10^43 hertz (To put this in perspective, a single photon at this frequency has about the same energy as a ton of TNT) nor more bits of memory than there are elementary particles in the universe (about 10^80).  But we are in thought-experiment land and here we are not bound by puny physical constraints.  Want a googolplex of RAM?  A clock rate equal to Graham's number?  You got it.

It turns out that when you buy a super-duper computer in thought-experiment land the details of the architecture no longer matter.  No matter what the details of your architecture, all super-duper computers have the exact same limitations.  And yes, super-duper computers do have limitations, the most famous of which is that they cannot compute the halting function for super-duper computers.

Note that I did not say that super-duper computers can't "solve the halting problem."  This is because there is no such thing as "the" halting problem; there are a lot of different halting problems, an infinite number of them in fact.  They are all of the form: will a given program halt or run forever on some particular input on some particular computer?  Notice that there are three parameters here: the program, the input, and the computer.  There are many (in fact, an infinite number of) halting problems for which a solution is easily found.  But to compute the halting function for a particular computer you have to solve all of the instances of the halting problem for that computer.

Turing's central result with respect to the halting problem is not that the halting function can't be computed, it is that no computer can compute its own halting function.  I'm not going to go through the proof (you can find a concise presentation at the bottom of this page).  The only thing that matters is that the proof is completely general.  It applies to any model of computation, not just Turing machines.

Note in particular that the result does not apply to one computer computing the halting function for a different computer.  A super-duper computer can easily compute the halting function for your MacBook Pro.  This is because your MBP only has a paltry terabyte of disk space and a few measly gigabytes of RAM and runs as a snails-pace of a few gigahertz.  A super-duper computer can, for example, simulate your MBP and keep track of all the states that the MBP goes through as it runs until one of two things happens: either the program halts, or the machine enters a state that it was previously in.  If the latter happens, the MBP is in an infinite loop.  Because there are only a finite number of possible states your MBP can be in, one or the other must happen sooner or later.

Now, the cost of actually carrying out this procedure is ridiculously high.  An SDC trying to compute the halting function for a machine with N bits of memory would need 2^N bits of memory.  But this doesn't matter.  We're in thought-experiment-land where resources are free.  We can have as much memory as we need as long as it's finite, and 2^N is finite for any finite N.  There might be better, more efficient algorithms for computing the halting function, but Turing's proof shows that such an algorithm would require M>N bits of memory to compute the halting function for a machine with N bits of memory.

Can we imagine a meta-super-duper computer that could compute the halting function for a super-duper computer?  Remember, an SDC's memory is unbounded.  At any given point in time an SDC can only be using a finite amount of memory, but there is no upper bound on this finite number the way there is for your MBP.   An MBP can be "maxed out" to the point where you can't add any more memory to it.  But an SDC has no such constraint.  We know (per Turing) that to compute the halting function on an SDC we somehow need a machine that is more powerful, and it's not clear how we would get more powerful than an SDC.

Happily, we don't actually need to say how we would do it.  We can just define a meta-super-duper-computer as one that can compute the halting function for an SDC somehow without actually specifying how it does this.  This is a legal maneuver in thought-experiment land.  It's actually no different than how we defined an SDC in the first place.  We never said how an SDC has access to an unbounded amount of memory, only that it does.

As an aside, we actually can describe how an MSDC could compute the halting function for an SDC.  For example, one possibility is to say that every operation that an MSDC performs takes half the time as the preceding operation.  The effectively allows an MSDC to perform an infinite number of operations in a finite amount of time, and that is enough for it to be able to compute the halting function.  Filling in this kind of detail can make you feel warm and fuzzy that you're reasoning still bears some relation to reality, but it's not necessary.  And in fact this is false comfort because we actually left the realm of physical reality back when we imagined an SDC, because SDCs do not and cannot really exist.

But whatever, back to thought-experiment-land.  An MSDC defined in this way is called an oracle for the halting problem for SDCs.  An MSDC can -- by definition! -- compute the halting function for an SDC, but not, of course, for an MSDC.  Remember, Turing's proof is completely general.  No computer can compute its own halting function.  It applies to MSDCs and SDCs and MacBook Pros and your pocket calculator.  But nothing stops us from imagining halting problem oracles and meta-oracles and meta-meta oracles, just as nothing stopped us from imagining a super-duper computer in the first place.

What does all this have to do with Turing Machines?  Well, it turns out that a Turing Machine is a super-duper computer.  It can run arbitrarily fast (as long as it's not infinitely fast) and it has an unbounded memory, and that's all it takes to make an SDC.  This is what is meant by the slogan "Turing machines are universal."  By the time you get to SDC territory, the details of the architecture no longer matter they way they do in the real world.  All SDCs have the same repertoire of capabilities and restrictions, and those capabilities and restrictions are exactly those of Turing machines, and also of dozens of others of computational models that have been proposed over the years that all turn out to be equivalent to each other.  Yes, there is an infinite hierarchy of more powerful machines that we can imagine on top of SDCs/TMs.  But since SDCs/TMs are already vastly more powerful than anything we could ever hope to actually build, they are a useful place to stop.  If a TM can't do something, no computer we can ever build can do it.

Again, just as an aside, consider for a moment the implications if we could build an oracle for the halting problem.  This machine could answer any mathematical question.  Want to figure out whether the Goldbach conjecture is true?  Just write a TM program that systematically searches for counterexamples and feed it to a halting oracle.  If the oracle says that the program runs forever, the conjecture is true.

So back to Akl.  He describes three kinds of functions that he claims are computable, but not by TMs.  As we have already seen, there is really not much sport in this.  We already know that the halting function for TMs can't be computed by TMs, but can be computed by a halting oracle.  The only thing that would be interesting is if these new functions that were not computable by TMs could be computed by something less magical than a halting oracle, a human brain for example, or a machine that we would actually have some hope of building.  And in fact some of Akl's functions can be computed by real physical systems!

So why isn't this bigger news?

It's because Akl's functions are not functions.  A function is a mathematical object with a very precise definition: it is a (possibly infinite) set of ordered tuples that defines a map from inputs to outputs.  Sets are static.  They don't change with time.  But we are interested in computation, and computation is a process, and processes are inherently embedded in time (that's what makes them proccesses rather than states).  Turing's model of computation is one that starts with the input to a function and ends with the output of the function having been computed without imposing any constraints on what happens in between other than that the time between the beginning and end of the process must be finite.

Akl's "functions" don't meet this criterion.  The way Akl comes up with things that TMs can't do is not by defining a function that a TM can't compute, but by adding constraints to the computational process that TMs can't fulfill.  Again, there is no sport in this.  You don't need anywhere near Akl's level of sophistication to show an example of this.  Here's a simple one: a TM cannot satisfy the constraint that the number of symbols on its tape must be even at every stage of the computation.  If the number of symbols is even, then as soon as the TM writes one additional symbol to the tape the constraint is violated.

But, you say, that is just so obviously stupid.  You can easily fix that (assuming you would even want to) by (for example) allowing the TM to write two symbols to the tape as a single step.  And you would be absolutely correct.  But every one of Akl's examples amounts to nothing more than a more complicated version of this exact same thing: a constraint of some sort that a machine has to obey during the computational process that a TM as normally defined can't meet, but which a minor variation on the TM theme easily can.  Specifically, all it takes is redefining what it means for a machine to make a "step", and more specifically, to allow multiple "classic" TM steps to be combined into a single meta-step.

Seriously, that is what all the fuss is about.  (Now perhaps you understand why I was reluctant to take up this topic in the first place.)

But I actually think that all of the preceding discussion is a bit of a red herring, and that there is really something deeper going on here.  A hint of this is provided by Publius's reference to Searle's Chinese Room, and an essay entitled "The Empty Brain" with the log-line, "Your brain does not process information, retrieve knowledge or store memories. In short: your brain is not a computer."  Here's the thesis:
Computers, quite literally, process information – numbers, letters, words, formulas, images. The information first has to be encoded into a format computers can use, which means patterns of ones and zeroes (‘bits’) organised into small chunks (‘bytes’). On my computer, each byte contains 8 bits, and a certain pattern of those bits stands for the letter d, another for the letter o, and another for the letter g. Side by side, those three bytes form the word dog. One single image – say, the photograph of my cat Henry on my desktop – is represented by a very specific pattern of a million of these bytes (‘one megabyte’), surrounded by some special characters that tell the computer to expect an image, not a word.
Quite simply, this essay betrays a deep ignorance of how computers work.  It is simply not true that data is stored in a computer in the straightforward manner that the author implies.  Images, for example, are hardly ever stored in raw form, with the rows of pixels corresponding in a straightforward manner to the contents of memory.  Images are invariably stored in compressed form, as jpgs or gifs, in which case the bits that represent the image appear more or less random to casual inspection.  Even text is nowhere near as straightforward as the author implies.  There may have been a time decades ago when all text was ascii and stored flat, but those days are long gone.  Nowadays we have unicode, PDF, HTML, base64-encoded, quoted-printable, and ten thousand other text formats, none of which map text to memory contents in a straightforward way.

Now, of course, if we scan your brain we won't find gifs and jpgs and pdfs.  Your brain processes information differently from your Macbook Pro.  But that doesn't mean that your brain is not a computer.  It (almost certainly) is.  Its architecture and software are very different from your MBP, and reverse-engineering it is very difficult.  But we have a pretty good handle on the basics: your brain is made of neurons that process electrical signals from your peripheral nervous system according to rules that comply with the laws of physics and so are expressible mathematically.  That's pretty much all it takes to make a computer.

It is true that your brain is not a Turing machine.  It is in fact much less powerful than a TM because a TM is a super-duper computer with unbounded memory and your brain isn't.  It is bounded.  We don't know exactly what the bound is, but there is no doubt that it's there.

It is actually not surprising that we don't fully understand our own brains. This is, in fact, impossible.  We are computers so, per Turing, we can't compute our own halting function.  But just because we can't do it doesn't mean it can't be done.  A halting oracle for the human brain is certainly possible in principle.  Whether it's possible in practice is an open question.  I'll give long odds against, but I wouldn't bet my entire life savings.