I was directed to this book (http://www-biba.inrialpes.fr/Jaynes/prob.html) in conversation here:
http://lesswrong.com/lw/3ox/bayesianism_versus_critical_rationalism/3ug7?context=1#3ug7
I was told it had a proof of Bayesian epistemology in the first two chapters. One of the things we were discussing is Popper's epistemology.
Here are those chapters:
http://www-biba.inrialpes.fr/Jaynes/cc01p.pdf
http://www-biba.inrialpes.fr/Jaynes/cc02m.pdf
I have not found any proof here that Bayesian epistemology is correct. There is not even an attempt to prove it. Various things are assumed in the first chapter. In the second chapter, some things are proven given those assumptions.
Some first chapter assumptions are incorrect or unargued. It begins with an example with a policeman, and says his conclusion is not a logical deduction because the evidence is logically consistent with his conclusion being false. I agree so far. Next it says "we will grant that it had a certain degree of validity". But I will not grant that. Popper's epistemology explains that *this is a mistake* (and Jaynes makes no attempt at all to address Popper's arguments). In any case, simply assuming his readers will grant his substantive claims is no way to argue.
The next sentences blithely assert that we all reason in this way. Jaynes' is basically presenting the issues of this kind of reasoning as his topic. This simply ignores Popper and makes no attempt to prove Jaynes' approach is correct.
Jaynes goes on to give syllogisms, which he calls "weaker" than deduction, which he acknowledges are not deductively correct. And then he just says we use that kind of reasoning all the time. That sort of assertion only appeals to the already converted. Jaynes starts with arguments which appeal to the *intuition* of his readers, not on arguments which could persuade someone who disagreed with him (that is, good rational arguments). Later when he gets into more mathematical stuff which doesn't (directly) rest on appeals to intution, it does rest on the ideas he (supposedly) established early on with his appeals to intuition.
The outline of the approach here is to quickly gloss over substantive philosophical assumptions, never provide serious arguments for them, take them as common sense, do not detail them, and then later provide arguments which are rigorous *given the assumptions glossed over earlier*. This is a mistake.
So we get, e.g., a section on Boolean Algebra which says it will state previous ideas more formally. This briefly acknowledges that the rigorous parts depend on the non-rigorous parts. Also the very important problem of carefully detailing how the mathematical objects discussed correspond to the real world things they are supposed to help us understand does not receive adequate attention.
Chapter 2 begins by saying we've now formulated our problem and the rest is just math. What I take from that is that the early assumptions won't be revisted but simply used as premises. So the rest is pointless if those early assumptions are mistaken, and Bayesian Epistemology cannot be proven in this way to anyone who doesn't grant the assumptions (such as a Popperian).
Moving on to Popper, Jaynes is ignorant of the topic and unscholarly. He writes:
http://www-biba.inrialpes.fr/Jaynes/crefsv.pdf
> Karl Popper is famous mostly through making a career out of the doctrine that theories may not be proved true, only false
This is pure fiction. Popper is a fallibilist and said (repeatedly) that theories cannot be proved false (or anything else).
It's important to criticize unscholarly books promoting myths about rival philosophers rather than addressing their actual arguments. That's a major flaw not just in a particular paragraph but in the author's way of thinking. It's especially relevant in this case since the author of the books tries to tell us about how to think.
Note that Yudkowsky made a similar unscholarly mistake, about the same rival philosopher, here:
http://yudkowsky.net/rational/bayes
> Previously, the most popular philosophy of science was probably Karl Popper's falsificationism - this is the old philosophy that the Bayesian revolution is currently dethroning. Karl Popper's idea that theories can be definitely falsified, but never definitely confirmed
Popper's philosophy is not falsificationism, it was never the most popular, and it is fallibilist: it says ideas cannot be definitely falsified. It's bad to make this kind of mistake about what a rival's basic claims are when claiming to be dethroning him. The correct method of dethroning a rival philosophy involves understanding what it does say and criticizing that.
If Bayesians wish to challenge Popper they should learn his ideas and address his arguments. For example he questioned the concept of positive support for ideas. Part of this argument involves asking the questions: 'What is support?' (This is not asking for its essential nature or a perfect definition, just to explain clearly and precisely what the support idea actually says) and 'What is the difference between "X supports Y" and "X is consistent with Y"?' If anyone has the answer, please tell me.
Really? Much of that seems questionable. There are many different ideas out there and practically speaking, there are too many ideas out there for people to have to deal with every single one. Sure, making incorrect arguments is bad. And making arguments against strawmen is very bad. But people don't have time actually research every single idea out there or even know which one's to look at. Now, I think that Popper is important enough and has relevant enough points that he should be on the short list of philosophers that people can grapple with at least to some limited extent. But frankly, speaking as someone who is convinced of that point, you are making a very weak case for it.
This paragraph seems to reflect a general problem you are having here in making assertions without providing any information other than vague claims of existence. I am for example aware of a large variety of arguments against induction (the consistency of anti-induction frameworks seems to be a major argument) but calling them "decisive" is a very strong claim, and isn't terribly relevant in so far as Bayesianism is not an inductive system in many senses of the term.
You've also referred to before to this claim that Popperian system can lead to moral knowledge and that's a claim I'd be very curious to hear expanded with a short summary of how that works. Generally when I see a claim that an epistemological system can create moral knowledge my initial guess is that someone has managed to bury the naturalistic fallacy somewhere or has managed to smuggle in additional moral premises that aren't really part of the epistemology. I'd be pleasantly surprised to see something that didn't function that way.
I haven't read it myself but I've been told that Earman's "Bayes or Bust" deals with a lot of the philosophical criticisms of Bayesianism as well as giving a lot of useful references. It should do a decent job in regards to the scholarly concerns.
As to Popper's criticism of Bayesianism, the discussion of it in LScD is quite small, which is understandable in that Bayesianism was not nearly as developed in that time as it is now. (You may incidentally be engaging in a classical philosophical fallacy here in focusing on a specific philosopher's personal work rather than the general framework of ideas that followed from it. There's a lot of criticism of Bayesianism that is not in Popper that is potentially strong. Not everything is about Popper.)
As a non-Bayesian, offense taken. You can't expect to go to a room full of people with a specific set of viewpoints offer a contrary view, act like the onus is on them to translate into your notation and terminology, and then be shocked when they don't listen to you. Moreover, knowing the basics of Cox's theorem is not asking you to "sound like a Bayesian" anyhow.
What? I don't know how to respond to that. I'm not sure an exclamation exists in standard English to express my response to that last sentence. I'm thinking of saying "By every deity in the full Tegmark ensemble" but maybe I should wait for a better time to use it. You are repeatedly complaining about people not knowing much about Popper while your baseline for Bayesianism is that you've read an incomplete Harry Potter fanfic? This fanfic hasn't even addressed Bayesianism other than in passing. This seems akin to someone thinking they understand rocketry because they've watched "Apollo 13".
Can I steal this?