Monthly Archives: January 2013

What Makes A Good Explanation?


I posted the following over at Jerry Coyne’s blog in the comments, and I like having a record of my comments so I’m posting it here as well :). If you’re sharp and have been reading my blog regularly, you’ll notice that my “precision” example is really just Bayes Theorem and the “simplicity” example is Occam’s Razor:

The thing we have to get out of the way first, when dealing with Creationists (or anyone with wacky ideas, like 9-11 truthers), is to determine what exactly constitutes a “good explanation”.

I think that there are certain criteria that all good explanations share, yet god-belief fails at all of them.

1) Mechanism. A good explanation explains more of the underlying mechanisms than bad explanations. If your faucet is leaking and you call a plumber over to fix it, the plumber will be able to explain the underlying mechanism behind what causes the faucet to leak. There’s no mechanism for positing god, other than “goddidit” or “sin”.

2) Testability. A good explanation lends itself to being testable. Your plumber will be able to reproduce the leak at command if he actually understands the underlying mechanism. And if the leak happens again and your plumber told you the underlying mechanism, you should be able to test his explanation and fix the leak yourself. God-belief is entirely untestable (well, it is, but it fails every single test).

3) Simplicity. Good explanations use fewer ad hoc claims — i.e. claims that are not testable and have no mechanism — to support itself. A plumber that does all of the above but then posits that the reason behind the leak is that you haven’t arranged the furniture in your house in a manner that resonates with the frequencies of the Crystals of Andraste is a worse explanation than one that leaves that out.

4) Precision. Good explanations exclude more possible evidence than bad explanations. Let’s say that you have two friends who collect marbles. One friend collects only black marbles while the other collects every single color marble he can get his hands on. If your plumbing problems started after both friends were over for a few hours, and a black marble was found in your pipes, it’s much more likely that your friend who only collects black marbles caused it than your friend who collects all marble colors; even though it’s known that both friends own black marbles. God-belief does not restrict the type of evidence would be seen as opposed to naturalism so god-belief would be analogous to the friend who collects every marble color imaginable. The more evidence god-belief allows, the less likely it is that it explains this one particular piece of evidence.

I would like to see Creationists come up with their own criteria for what constitutes a “good explanation” using examples from real life which also supports their Creationism. Usually they fall prey to simplistic thinking like the tornado-in-a-junkyard strawman, claiming that evolution breaks the 2nd law of thermodynamics, the watchmaker fallacy, appeals to ignorance (“no one knows how this happens, therefore goddidit”) or the fallacy of composition (e.g. everything we know of in the universe was made by someone, therefore the universe was made by someone).

Someone else made a good additional comment:

IOW, they usually make what they suppose is a negative case against evolution. They don’t make a positive case for creation.

I’ve seen all the negative arguments above, but I’m sure I’m not particularly well-versed in creationist arguments; I’d be interested to know if they do try to present positive evidence.

Which basically boils down to: Just because you suspect something is a lie, doesn’t mean you know the truth.


Posted by on January 31, 2013 in Bayes, creationism


This Is Your Brain On Music

Friday night blues

(Friends of mine, Naomi and Joy, blues dancing)

Being a musician, this article is massive awesome-sauce: How music touches the brain

Responding to Argentinian tango

Using functional magnetic resonance imaging (fMRI), the research team, led by Dr. Vinoo Alluri from the University of Jyväskylä, Finland, recorded the brain responses of individuals who were listening to a piece of modern Argentinian tango.


The whole brain reacts to music

Comparing the brain responses and the musical features led to an interesting new discovery: the researchers found that listening to music activates not only the auditory areas of the brain, but also employs large-scale neural networks.

For instance, they discovered that the processing of musical pulse activates motor areas in the brain, supporting the idea that music and movement are closely intertwined.

Limbic areas of the brain, known to be associated with emotions, were found to be involved in rhythm and tonality processing.

And the processing of timbre was associated with activations in the so-called default mode network, which is assumed to be associated with mind-wandering and creativity.

And they say that science can’t tell us anything about art.

What’s interesting is how something like this would evolve. The only other species that can “hear” music like we do are birds, and its entire purpose seems to be sexual communication of sorts. Yes, I realize there are YouTube videos of dogs and such “dancing” to music, but they don’t actually hear the music; they can’t hear a beat and thus won’t actually be dancing to the music. Anyone who thinks so is just engaging in rampant anthrpomorphisim.

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Posted by on January 25, 2013 in cognitive science


Logical Fallacies as Weak Bayesian Evidence: Correlation Doesn’t Equal Causation


See my post about the related logical fallacy Post Hoc Ergo Propter Hoc.


Train Philosophers with Pearl and Kahneman, not Plato and Kant


A recent post over at R. Joseph Hoffmann’s blog reminded me of a post over at Less Wrong: Train Philosophers with Pearl and Kahneman, not Plato and Kant. Luke proposes that philosophy is a diseased discipline and should be training people to think critically using modern methods of rationality (e.g. Pearl), not to think critically using ancient methods of rationality (e.g. Aristotle):

Philosophical training should begin with the latest and greatest formal methods (“Pearl” for the probabilistic graphical models made famous in Pearl 1988), and the latest and greatest science (“Kahneman” for the science of human reasoning reviewed in Kahneman 2011). Beginning with Plato and Kant (and company), as most universities do today, both (1) filters for inexact thinkers, as Russell suggested, and (2) teaches people to have too much respect for failed philosophical methods that are out of touch with 20th century breakthroughs in math and science.

So, I recommend we teach young philosophy students:

more Bayesian rationality, heuristics and biases, & debiasing less informal “critical thinking skills”;

more mathematical logic & theory of computation, less term logic;

more probability theory & Bayesian scientific method, less pre-1980 philosophy of science;

more psychology of concepts & machine learning, less conceptual analysis;

more formal epistemology & computational epistemology, less pre-1980 epistemology;

more physics & cosmology,less pre-1980 metaphysics; [me: metaphysics etymologically means “after physics” so I would think that metaphysics should only be engaged after one has a firm grasp of plain ol’ physics]

more psychology of choice, less philosophy of free will;

more moral psychology, decision theory, and game theory, less intuitionist moral philosophy;

more cognitive psychology & cognitive neuroscience, less pre-1980 philosophy of mind;

more linguistics & psycholinguistics, less pre-1980 philosophy of language;

more neuroaesthetics, less aesthetics;

more causal models & psychology of causal perception, less pre-1980 theories of causation.

Of course, the reason that Luke proposes these things is because he is the CEO of an organization that is focused on building friendly AI. Which means he has to know how to correctly design a thinking machine by the very nature of his work. As Luke says elsewhere, the tool we use to philosophize is the brain, and if we don’t know how our tool works we will use it poorly. Which is why philosophers should be studying how brains actually work, making cognitive science a mandatory field of study for those who want to “use their tool properly”.

I have a post that summarizes a bit of Kahneman’s thesis in Thinking, Fast and Slow that I wrote a while back.

Luke’s second point, that we should be Bayesian rationalists, not “term logic” rationalists is probably (heh) more debatable. Again, Luke is coming from an AI framework which doesn’t afford the simplicity of deduction’s major premise, minor premise, conclusion; of the binary true/false of basic logic. An AI would be programmed using mathematical logic for determining the best course of action. And since we don’t live in a world of deductive certainty, a person who is programming a brain would use a method that can handle uncertainty, which would be a Bayesian form of rationality.

This is one of the reasons why I started looking at some basic logical fallacies that aren’t necessarily fallacies from a probability context. An argument from silence, for example, fails as a deductive argument. But it is not a failure or probability; it would actually be a reasonable inference. That being said, simply parroting “that’s a logical fallacy!” is pretty much a worthless form of engagement with reality, since almost all of our decisions are ones that are made from a frame of uncertainty. The funny thing is, evolution programmed our brains for rudimentary Bayesian rationality. Our education system of rote learning helps to dismantle it.

Luke then goes on to state:

So, my own “intro to philosophy” mega-course might be guided by the following core readings:

  1. Stanovich, Rationality and the Reflective Mind (2010)
  2. Hinman, Fundamentals of Mathematical Logic (2005)
  3. Russell & Norvig, Artificial Intelligence: A Modern Approach (3rd edition, 2009) — contains chapters which briefly introduce probability theory, probabilistic graphical models, computational decision theory and game theory, knowledge representation, machine learning, computational epistemology, and other useful subjects
  4. Sipser, Introduction to the Theory of Computation (3rd edition, 2012) — relevant to lots of philosophical problems, as discussed in Aaronson (2011)
  5. Howson & Urbach, Scientific Reasoning: The Bayesian Approach (3rd edition, 2005)
  6. Holyoak & Morrison (eds.), The Oxford Handbook of Thinking and Reasoning (2012) — contains chapters which briefly introduce the psychology of knowledge representation, concepts, categories, causal learning, explanation, argument, decision making, judgment heuristics, moral judgment, behavioral game theory, problem solving, creativity, and other useful subjects
  7. Dolan & Sharot (eds.), Neuroscience of Preference and Choice (2011)
  8. Krane, Modern Physics (3rd edition, 2012) — includes a brief introduction to cosmology

Looks like I’ve got some reading to do!

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Posted by on January 22, 2013 in Bayes, cognitive science


Luke: Adapting from Marcion or Matthew?

So it’s been my working hypothesis that Luke is following Matthew and that Q didn’t exist. There is another line of evidence that may even suggest that Marcion’s gospel should be added into the mix as a “fourth Synoptic”.

In Marcion’s gospel, Jesus descends from heaven right into Capernaum and begins preaching. It’s only later that Marcion’s Jesus goes to Nazareth. In Luke, however, Jesus doesn’t go to Capernaum until 4.31, where the people there are amazed at his preaching and amazed that he removed an unclean spirit from a parishioner; implying that Jesus had never been to Capernaum before. In the pericope right before that at Luke 4.23, Jesus claims that he was in Capernaum before preaching in Nazareth. Of course, in Luke, Jesus didn’t start preaching or doing any miracles until chapter 4. The chapters before that, Jesus is born, gets baptized, and immediately goes into the wilderness to be tested. After testing in the wilderness, he goes to Nazareth.

To make an error like that implies that Luke is redacting an earlier source, chopping up bits and pieces to rearrange them for his theological needs. Since neither Marcion nor Matthew have this error, and the ‘Physician, heal yourself!’ line is not in Matt, it probably means that Luke is redacting Marcion at this point.

In general, Luke’s narrative logic in this pericope makes little sense while Marcion’s makes a bit of sense. At first those in the synagogue are pleased with Jesus’ reading of scripture (e.g. Lk 4.22 All spoke well of him and were amazed at the gracious words that came from his lips.) and then out of nowhere Jesus accuses them of being skeptical and demanding that he do there in Nazareth what he did in Capernaum (which, as I’ve just discussed, he hadn’t been to Capernaum at this point). This drives the people into such a rage that they attempt to throw him off a cliff which he just passes through as though he were a ghost.

Why would Jesus accuse them of skepticism when they were pleased with his preaching? It doesn’t make sense.

Marcion’s version makes a bit more sense. After speaking, the people are confused about his speaking, and Jesus insinuates they are skeptical and probably want him to do here in Nazareth what he did in Capernaum (which makes sense, since he drove out an unclean spirit [i.e. ‘Physician, heal yourself!’] in Capernaum before going to Nazareth in Marcion). The people are driven into a rage and attempt to toss him off a cliff, in which, since Jesus is a phantom, he decides to pass through the crowd untouched.

Of course, in total this pericope makes sense for Marcion to write, since Marcion’s Jesus was indeed a “ghost” or a phantom, being a docetist and all. Luke, being an anti-docetist, doesn’t should not create a pericope like this that implies docetism.

Tertullian’s apologetic for this is pretty bad:

Here at once, when I observe that they laid their hands on Him, I cannot help drawing a conclusion respecting His bodily substance, which cannot be believed to have been a phantom, since it was capable of being touched and even violently handled, when He was seized and taken and led to the very brink of a precipice. For although He escaped through the midst of them, He had already experienced their rough treatment, and afterwards went His way, no doubt because the crowd (as usually happens) gave way, or was even broken through; but not because it was eluded as by an impalpable disguise, which, if there had been such, would not at all have submitted to any touch.

(Against Marcion 4.8.10-13)

An alternative hypothesis is that Luke had this error and Marcion corrected it. But we would then have to answer why Luke had this error in the first place. Another alternative is that both Luke and Marcion are adapting an older source, a sort of pre-Luke (see J. Tyson’s Marcion and Luke-Acts p 83-85). This still wouldn’t answer why Luke had the error in the first place.

A sticking point with this, however, is that Luke has included in this section the town name “Nazara” that Matt 4.13 also used; albeit in a different pericope (Lk 4.16 Καὶ ἦλθεν εἰς Ναζαρά, οὗ ἦν τεθραμμένος :: And he went into Nazara, where he was brought up // // Mt 4.13 καὶ καταλιπὼν τὴν Ναζαρὰ ἐλθὼν κατῴκησεν εἰς Καφαρναοὺμ :: and leaving from Nazara went to settle in Capernaum). In short, this town name “Nazara” is the grammatically correct interpretation of what “Nazarene” means, if one assumes Nazarene is a gentilic. Matt assumed, at 4.13, that Mark’s “Nazarene” was a gentilic.

Kinda like saying Canadian. In English, if we call someone an XYZ-ian, we would assume that this person was from XYZ. Similarly, in Koine Greek, if someone is a XYZ-ene, then they are from XYZ. So at Mark 5.1, Jesus goes into the region “of the Gerasenes” (Γερασηνῶν::Gerasenon; gen. pl.), which means that he went to Gerasa. The same logic would hold for Nazarene which would mean someone from Nazara. The move from Nazarene to Nazareth seems to have taken time to develop. This gentilic is corroborated by some Gnostic sources. In the Gospel of Philip, the author says that Nazara means “truth”, thus Jesus is one who comes from truth.

Anyway, it is impossible to tell if Marcion had Nazara where Luke has it, since the only source that only implies that Marcion had this section is written in Latin (Tertullian). Not only that, but the W-H NT is a reconstruction of the earliest manuscripts. This means that Nazara might have been replaced with Nazareth by copyists in later copies by the time of Tertullian.

Nazara is evidence that Matt is among Luke’s sources, but I don’t know if Marcion also knew about Matt. Marcion having Nazara would be evidence in favor of him knowing Matt.

So we have three related weights of evidence in favor of Luke rewriting Marcion and/or Matt from this section:

1. Jesus refering to miracles in Capenaum before even going there
2. A narrative that doesn’t make sense of why the synagogue would go from glowing praises to raging anger in just a couple of verses
3. A pericope’s conclusion that assumes some type of docetism

We also have some weights that argue that Marcion edited Luke:

1. Scholarly consensus that Marcion did so
2. All ancient sources (besides Marcion himself and the Marcionites) allege that Marcion mutilated Luke
3. Scholarly consensus that Luke was written about 40 years before Marcion became active; Luke is alleged to have been written around 80 CE and Marcion being active around 120 – 140 CE according to the majority of NT scholars.

Quite honestly, I think the arguments in favor of Marcion editing Luke, that I’ve enumerated above, are all bullshit. I can’t abide by a scholarly consensus that is based mostly on cultural inertia and trying not to offend Christians; “pursue the truth no matter where it lies”, and all that. Though it seems like the consensus is moving a bit more towards Luke (and Acts of the Apostles) having been written later than the standard time of 80 CE to at least the time period after Josephus. But I’ll factor in the consensus in my little analysis.

If I may be so bold, I think I can represent this using some subjective Bayescraft in a following post.


Posted by on January 16, 2013 in marcion


The Outsider Test for Faith via Bayes


I posted the following comment over at Richard Carrier’s blog. I thought it was relevant to my blog, so I’m reposting it here.

I arrived at the Outsider Test for Faith (OFT) looking at BT from a different angle. What it is basically trying to point out is that there’s no necessary relationship between being born into a Christian household (i.e. your parents, friends, etc. are all Christians) which is a pretty strong determining factor in most people being Christians, and Christianity actually being true. The evidence that we have is the geographical distribution of the various religions, in this case I thought that P(E) should be the probability, or percentage, of Christians who were raised as Christians; whose family, friends, etc. are also Christians. This would mean that P(E) is somewhere around 30%. 33% of the world is Christian and there are obviously some Christians who converted to Christianity from other religions.

P(E | H), then, would be the probability of the evidence given that Christianity is true, and P(E | ~H) would be the probability of the evidence at hand given some other reason (e.g. Islam is true, atheism is true, etc.). Of course, P(E) = P(E | H)*P(H) + P(E | ~H)*P(~H), the denominator for BT. I even assumed for the sake of argument that P(H), the probability that Christianity is true, is some ridiculously high number like 97% just to prevent Christians from saying that I’m biasing the argument against Christianity. So if P(H) is 97% then P(~H) is 3%. Now we have P(E) = P(E | H)*P(H) + P(E | ~H)*P(~H), or 30% = P(E | H) * 97% + P(E | ~H) * 3%. If we assume that P(E | H) is a high number, again, to bias towards Christianity being true, we end up skewing things ridiculously. The equation would then become a simple enough algebraic one to solve in the manner of 3 = 97 + .3x, but with P(E | H) being 1, it forces P(E | ~H) to be a negative number, which makes no sense.

Playing around with different values for both P(E | H) and P(E | ~H), it would seem to me that the only fair values would be to have P(E | H) = P(E | ~H), which is statistical independence. It literally means that whatever religion you were raised in has absolutely no relationship with that religion being true; it also means that it has no bearing on whether your religion is false. For both, you would need some other evidence to update your prior against. Of course, if a Christian appealed to something like “it just feels true” or “I had an experience I can’t explain, therefore Christianity is true” other religions use the same exact sort of argument, so we would end up in the same situation that P(E | H) = P(E | ~H) with E being the religious experience and H being the probability that the religion is true. So again, you would need some other evidence to update against which is basically the fundamental premise behind the OTF.

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Posted by on January 9, 2013 in Bayes


Are Science and Religion Compatible?


On the face of it, most people assume the positive, since there are religious scientists. Or because there are many scientific discoveries that were uncovered by religious people. Et cetera. But this is a massively simplistic view of the problem.

First of all, this phenomenon of religious scientists is, in my opinion, adequately explained by thinking of science, or the scientific method, as a sort of social ritual. In this view, the scientific method is just another social forum, like playing football. You don’t use the rules of football for religion, duh! That would make no sense; you don’t bring footballs to church and you don’t bring Jesus to the football field (unless you’re Tim Tebow…). Just like football has a bunch of rules designed only for playing football, religious scientists also believe that there are social rules for doing science. And again, you don’t bring the social rules, the agreed upon social contract for “doing science”, to church anymore than you bring the social rules for churchgoing to the lab.

Play the rules of the game — whether the scientific method or football — according to the letter, and you will be successful in that arena. Falsifiability is restricted to the domain of science just like not going offsides before the snap is restricted to the football field. So in this sense, religion is compatible with science just like religion is compatible with football.

Secondly, this papers over the pretty uncontroversial human activity of rationalization. Much like a vegetarian who eats meat but uses some rationalization to explain away why their meat eating isn’t inconsistent with their vegetarianism.

If my reasoning above is true, then they both explain why science and religion are “compatible”. Of course, this means “compatible” in only the most superficially coincidental ways. Much like being a nice guy is compatible with being a rapist. Of course, if my reasoning above is true, then this in and of itself means that science and religion are not compatible. Why? Because when we talk about compatibility, we means occurring at the same time at the same place. Religious scientists do not practice both religious thought and scientific thought at the same time because they consider them to be two separate social contracts; they’re no more compatible than oil and water. Just because you can have both oil and water in the same glass this doesn’t mean they’re compatible.

The pithy saying (and equivocation fallacy) “science tells us how the heavens go, religion tells us how to go to heaven” is itself a ringing endorsement of the bullshit idea that science and religion are compatible. Not only that, but as an aside, “heaven” is the translation of the word οὐρανός (ouranos) which was transliterated into Latin as Uranus. Which is how I feel about the whole thing ;-).

So really, if you want to bypass all of this argumentation when we get to the question of whether science and religion are compatible, instead of asking that question one should ask whether religious claims are falsifiable. If you say yes, then that answers your question of whether science and religion are compatible. If you say no, then this is also the answer to whether science and religion are compatible.

But if we look at the fundamental premises behind the epistemology of religiosity and the epistemology of the scientific method, there is a massive, irreconcilable contradiction.

Science, more than just assuming the natural, assumes reductionism. Big things can be broken down into their constituent parts and analyzed bit by bit. And then those constituent parts themselves can be further broken down, and those parts can be analyzed. The budding engineer who takes apart a radio or computer is assuming the necessary precursor for scientific thinking. Religion, on the other hand, is vehemently not reductionist. The fundamental particle in religious thought is not the quark, gluon, or Higgs-Boson. It’s the mind. Of course, this doesn’t apply wholesale to modern religions like Christianity but for older religious thought like animism. But Christianity still has the mind as the fundamental particle for living things.

So not only are science and religion incompatible, they will never be compatible due to reductionism. Unless and of course the mind actually is a fundamental particle instead of being an emergent property of the reducible brain.

Of course, I don’t think that science is just some sort of social ritual. I think things like falsifiability follows necessarily from the laws of logic. So religion isn’t just incompatible with science. It is incompatible with logic.

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