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Bayes’ supercool theorem promotes “superstition”?


John Horgan at Scientific American thinks so:

“Why does a mathematical concept generate this strange enthusiasm in its students? What is the so-called Bayesian Revolution now sweeping through the sciences, which claims to subsume even the experimental method itself as a special case? What is the secret that the adherents of Bayes know? What is the light that they have seen? Soon you will know. Soon you will be one of us.” Yudkowsky is kidding. Or is he?

Given all this hoopla, I’ve tried to get to the bottom of Bayes, once and for all.

Horgan offers helpful suggestions. Of course, Bayesianism could amount to nothing more than a sophisticate’s way of avoiding common sense reasoning in order to make himself look smarter than he is and know better than he does. Okay, that’s just a conjecture.

Seriously, Horgan thinks Bayesian theory yields some possibly useful results in interpreting health care tests:

Here is my more general statement of that principle: The plausibility of your belief depends on the degree to which your belief–and only your belief–explains the evidence for it. The more alternative explanations there are for the evidence, the less plausible your belief is. That, to me, is the essence of Bayes’ theorem.

Of course, not only are there alternative explanations for just about everything, but people sharply disagree on which ones are plausible. That said,

And as I mentioned above, some string and multiverse enthusiasts are embracing Bayesian analysis. Why? Because the enthusiasts are tired of hearing that string and multiverse theories are unfalsifiable and hence unscientific, and Bayes’ theorem allows them to present the theories in a more favorable light. In this case, Bayes’ theorem, far from counteracting confirmation bias, enables it.

I’m nonetheless fascinated by Bayes’ theorem. It reminds me of the theory of evolution, another idea that seems tautologically simple or dauntingly deep, depending on how you view it, and that has inspired abundant nonsense as well as profound insights.More.

Well, for nonsense, look no further than evolutionary psychology, which has the distinction of actually being a self-refuting theory. If it is really true that we can explain why a Hungarian-born Canadian tips at restaurants in China on the basis of what happened on the African savannah 2 mya, the most reasonable conclusion is that no evolution occurred in all that time. It should be called a theory of stasis then, not a theory of evolution. Maybe Bayes’ theory can do them a makeover.

Mathematician Peter Woit comments

I’ve never been able to really make sense of many of the arguments about “Bayes’s Theorem”, and the recent attempts to justify string theory using this just seemed bizarre. John Horgan has a great explanation of what is going on here, including this take on the Bayes/string theory/multiverse business.

So Horgan’s analysis is doubtless a keeper.

See also: Scientific American Science writer John Horgan still doubts cosmic inflation …

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I'm sure Bayesian statistics has useful applications but the Bayesian Brain hypothesis, according to which the brain uses probability to make sense of the world is right up there with the flat earth hypothesis. The truth is that the brain expects a perfectly deterministic world. Mapou

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