Bayesianism versus Critical Rationalism

Jayson_Virissimo

I have just rediscovered an article by Max Albert on my hard drive which I never got around to reading that might interest others on Less Wrong. You can find the article here. It is an argument against Bayesianism and for Critical Rationalism (of Karl Popper fame).

Abstract:

Economists claim that principles of rationality are normative principles. Nevertheless,
they go on to explain why it is in a person’s own interest to be rational. If this were true,
being rational itself would be a means to an end, and rationality could be interpreted in
a non-normative or naturalistic way. The alternative is not attractive: if the only argument
in favor of principles of rationality were their intrinsic appeal, a commitment to
rationality would be irrational, making the notion of rationality self-defeating. A comprehensive
conception of rationality should recommend itself: it should be rational to be
rational. Moreover, since rational action requires rational beliefs concerning means-ends
relations, a naturalistic conception of rationality has to cover rational belief formation including
the belief that it is rational to be rational. The paper considers four conceptions
of rationality and asks whether they can deliver the goods: Bayesianism, perfect rationality
(just in case that it differs from Bayesianism), ecological rationality (as a version of
bounded rationality), and critical rationality, the conception of rationality characterizing
critical rationalism.

Any thoughts?

A good nutshell description of the type of Bayesianism that many LWers think correct is objective Bayesianism with critical rationalism-like underpinnings. Where recursive justification hits bottom is particularly relevant. On my cursory skim, Albert only seems to be addressing "subjective" Bayesianism which allows for any choice of prior.

4XiXiDu15y

For people like me who have no clue, if you scroll down a bit here there is a comparison (so you get a vague idea): * Subjective Bayesians emphasize the relative lack of rational constraints on prior probabilities. * Objective Bayesians (e.g., Jaynes and Rosenkrantz) emphasize the extent to which prior probabilities are rationally constrained. More here: And of course Critical rationalism: * Critical rationalism explicitly proposes a third decision rule for rational belief formation: it is rational to believe a hypothesis if it has so far withstood serious criticism better than its competitors.

5Matt_Simpson15y

I'll add that a decent summary of the position espoused in Where recursive justification hits bottom (linked in the grandparent) is that critical rationalism (or something like it) entails objective Bayesianism. It both entails the use of Baye's rule to update on information and it entails a set of correct priors.

1Jayson_Virissimo15y

Thanks for helping me realize that Critical Rationalism and Bayesianism can be compliments rather than substitutes.

2Elliot Temple15y

FYI that is a misleading statement of Critical Rationalism. For one thing, Popper was not a "belief philosopher" so he wouldn't have stated it quite like that. There are a lot of misleading statements about CR floating around. Most come from its opponents trying to make sense of it on their own terms. In trying to formulate it in a way that makes sense given their anti-CR premises, they change it. It's best to read primary sources for this.

It seems to think the problem of the priors does in Bayesianism :-(

Popper seems outdated. Rejecting induction completely is not very realistic.

2Jayson_Virissimo15y

Critical Rationalism has advanced somewhat since Popper. I think Hume would agree.

2timtyler15y

Not very significantly. The revolution happened mostly without them.

5Jayson_Virissimo15y

After reconsidering your statement, I have come to agree.

1Elliot Temple15y

Who do you think advanced CR? I think only David Deutsch has improved on Popper.

2Jayson_Virissimo15y

I had in mind Miller and Deutsch.

2Elliot Temple15y

Which Miller publication or argument?

5Jayson_Virissimo15y

Critical Rationalism: A Restatement and Defense and Out of Error: Further Essays On Critical Rationalism.

1Elliot Temple15y

Thanks I ordered them. I'd only read individual articles of his.

-2[anonymous]15y

Hume would agree because he never accepted the full force of his own argument. He couldn't imagine how people can create knowledge without induction even though he could see that induction is impossible. It took Popper to explain how knowledge can be created without induction.

I apologise for this, but I really don't see how anyone could go through those studies without losing all faith in human intuition.

I haven't got any faith in human intuition. That's not what I said.

I have never read anything written by him although after this conversation I am planning to.

OK fair enough.

Oh the book is here: http://bayes.wustl.edu/etj/prob/book.pdf

That was easy.

I don't know the etiquette or format of this website well or how it works. When I have comments on the book, would it make sense to start a new thread or post somewhere/somehow?

Can you be a Popperian and conjecture Bayesianism?

You can conjecture Bayes' theorem. You can also conjecture all the rest, however some things (such as induction, justificationism, foundationalism) contradict Popper's epistemology. So at least one of them has a mistake to fix. Fixing that may or may not lead to drastic changes, abandonment of the main ideas, etc

The point that I do disagree with is the proposed asymmetry between confirmation and falsification.

That is a purely logical point Popper used to criticize some mistaken ideas. Are you disputing the logic? If you're merely disputing the premises, it doesn't really matter because its purpose is to criticize people who use those premises on their own terms.

In my view neither the black swan or the white swan proves anything with certainty,

Agreed.

but both do provide some evidence. It happens in this case that one piece of evidence is very strong while the other is very weak, in fact they are pretty much at opposite extremes of the full spectrum of evidence encountered in the real world. This does not mean there is a difference of type.

I think you are claiming that seeing a white swan is positive support for the assertion that all swans are white. (If not, please clarify). If so, this gets into important issues. Popper disputed the idea of positive support. The criticism of the concept begins by considering: what is support? And in particular, what is the difference between "X supports Y" and "X is consistent with Y"?

I also doubt that any philosophy could manage without either circularity or assumptions, explicit or otherwise. As I see it when you start thinking you need something to begin your inference, logic derives truths form other truths, it cannot manufacture them out of a vacuum.

Questioning this was one of Popper's insights. The reason most people doubt it is possible is because, since Aristotle, pretty much all epistemology has taken this for granted. These ideas seeped into our culture and became common sense.

What's weird about the situation is that most people are so attached to them that they are willing to accept circular arguments, arbitrary foundations, or other things like that. Those are OK! But that Popper might have a point is hard to swallow. I find circular arguments rather more doubtful than doing without what Popperians refer to broadly as "justification". I think it's amazing that people run into circularity or other similar problems and still don't want to rethink all their premises. (No offense intended. Everyone has biases, and if we try to overcome them we can become less wrong about some matters, and stating guesses at what might be biases can help with that.)

All the circularity and foundations stem from seeking to justify ideas. To show they are correct. Popper's epistemology is different: ideas never have any positive support, confirmation, verification, justification, high probability, etc... So how do we act? How do we decide which idea is better than the others? We can differentiate ideas by criticism. When we see a mistake in an idea, we criticize it (criticism = explaining a mistake/flaw). That refutes the idea. We should act on or use non-refuted ideas in preference over refuted ideas.

That's the very short outline, but does that make any sense?

You can conjecture Bayes' theorem. You can also conjecture all the rest, however some things (such as induction, justificationism, foundationalism) contradict Popper's epistemology. So at least one of them has a mistake to fix. Fixing that may or may not lead to drastic changes, abandonment of the main ideas, etc

Fully agreed. In principle, if Popper's epistemology is of the second, self-modifying type, there would be nothing wrong with drastic changes. One could argue that something like that is exactly how I arrived at my current beliefs, I wasn't born... (read more)

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Bayesianism versus Critical Rationalism

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