4 ms·

ET Jaynes is the best! Read the whole book! http://bayes.wustl.edu/etj/prob/book.pdf http://bayes.wustl.edu/etj/prob/book.pdf

bkcooper 12y ago
It's certainly worth looking at. I personally find Jaynes's acerbic commentary entertaining, although I imagine it grates for many. His overall view of probability is satisfyingly coherent, but I do not consider myself sufficiently expert to assess whether it is meaningfully better than the alternatives. And there are places where I believe he is just wrong, e.g. he seems to reject Bell's inequality and view quantum probability as just another case of limited information. There are also times, like in the chapter linked in the parent, where his zeal is bothersome. He begins the discussion of ESP by saying it would be too dogmatic to assign a probability of 0 to ESP. But, when faced with the evidence, he just throws in a bunch of other possible hypotheses that can explain it: Therefore, this kind of experiment can never convince me of the reality of Mrs. Stewart’s ESP; not because I assert Pf = 0 dogmatically at the start, but because the veriﬁable facts can be accounted for by many alternative hypotheses, every one of which I consider inherently more plausible than Hf, and none of which is ruled out by the information available to me. Of course the choice of priors for those other hypotheses were subjective, and there's no limit on how many other hypotheses one might add to explain away unpleasant data. This strikes me as more rationalizing than rationalist.
- dthunt 12y ago
  Really? Do you actually think that Jaynes is being unreasonable when he assigns ESP a prior that is lower than "has some sort of trick" or some other thing that generally turns out to be the explanatory factor for a magician? He's saying that ESP is an unlikely explanation. He's saying that it is Probably Something Else. The experimental data cannot distinguish them. That's why it's not compelling. It has very little to do with rationalization. It's a terrible test.
  - bkcooper 12y ago
    No, clearly the underlying mechanism that he describes is good. However, as he admits in the passage I quote, he is so unconvinced by the possibility of ESP that no tests of this sort could ever convince him. The issue isn't just that naive tests of ESP are easily cheated, either, because you can apply the same logic to more stringently controlled tests. It just seems more honest to me to admit up front in this situation that you cannot be convinced of ESP (give it prior probability of 0) instead of playing these games to essentially shift the "dogmatism" onto the choice of alternative hypotheses and their prior probabilities (which seem chosen to enforce a posterior probability of ESP of ~0.)
    - dthunt 12y ago
      Look. I'll explain it really simple. He's saying it has to be > 0, because he is unwilling to rule out ESP as a logical possibility. If he assigned it 0, no matter how good the experimental design was, and no matter what the test was, he would be unmovable from this position. 0 is forbidden if you want to accept it as a possibility. This is why he says this. He also is being honest about his appraisal of the general likelihood of ESP. It's very low. He doesn't bother to explain how low because it turns out it's IRRELEVANT. You literally have to believe ESP is the most likely explanation among all the usual alternatives ALREADY in order to think it was ESP after ingesting the data, because the data in this test is not EVIDENCE for ESP, because P(E|sort of works ESP) and P(E|one of the assistants wore glasses and Stewart could see some reflections) or whatever your remotely plausible alternative - all look pretty identical. It is not evidence, in the sense that you cannot do 500, 37,100, or a 1 million card guessing attempts in this setup with this level of detail and expect it to shift belief of a rational agent. The ratio between the priors of the usual suspects is going to look the same as your ratio of posteriors between all the hypotheses after the test. In order to convince someone of ESP rationally, you need to demonstrate that it is extremely difficult to cheat under the test conditions, in the sense that P(E|trickery) goes down. Your alternative theory ISN'T the null hypothesis. It's a garden variety non-magical trickster, which exist in great numbers, whereas nobody has yet seen even a single instance of ESP as it is normally meant.
      - 12y ago
- loup-vaillant 12y ago
  > His overall view of probability is satisfyingly coherent, but I do not consider myself sufficiently expert to assess whether it is meaningfully better than the alternatives. You're probably under-confident. I have read the first two chapters, and they just felt obvious to me. While I understand we could refine probability theory, I think we can say that anything that contradicts it is probably bollocks. > And there are places where I believe he is just wrong, e.g. he seems to reject Bell's inequality and view quantum probability as just another case of limited information. There is a part where he's definitely right, though: the so called "quantum probability" is not a probability at all. No matter how much it looks like a probability, it's something out there in the territory, and probability is in the mind. Besides, the idea that complex numbers (amplitude) could be probabilities is rather ridiculous. And of course, the then popular interpretation of quantum mechanics was crazy: it was either contradicting or denying the very equations that made so good predictions in the first place! Now he could have criticized Many World as well, for it may seem it's a cop-out as well. We have reduced the Born statistics to an anthropic problem, but we haven't solved it yet.
dthunt 12y ago
I very much like the way he lays out the groundwork. It answers fairly directly a lot of criticisms I've seen leveled at probability.
asgard1024 12y ago
Is that a full book? It seems that it has only first 3 chapters. However, I found the other chapters in the directory with the original submission, but they seem to weirdly overlap with content.
- thetwiceler 12y ago
  Oh, I didn't realize that. Well, the book is Probability Theory: The Logic of Science ET Jaynes 2003 I highly suggest buying it or finding it from your library!
  - dthunt 12y ago
    The full text of a draft version is out there, actually. I bought my copy, though. :)

bkcooper 12y ago

It's certainly worth looking at. I personally find Jaynes's acerbic commentary entertaining, although I imagine it grates for many. His overall view of probability is satisfyingly coherent, but I do not consider myself sufficiently expert to assess whether it is meaningfully better than the alternatives. And there are places where I believe he is just wrong, e.g. he seems to reject Bell's inequality and view quantum probability as just another case of limited information. There are also times, like in the chapter linked in the parent, where his zeal is bothersome. He begins the discussion of ESP by saying it would be too dogmatic to assign a probability of 0 to ESP. But, when faced with the evidence, he just throws in a bunch of other possible hypotheses that can explain it: Therefore, this kind of experiment can never convince me of the reality of Mrs. Stewart’s ESP; not because I assert Pf = 0 dogmatically at the start, but because the veriﬁable facts can be accounted for by many alternative hypotheses, every one of which I consider inherently more plausible than Hf, and none of which is ruled out by the information available to me. Of course the choice of priors for those other hypotheses were subjective, and there's no limit on how many other hypotheses one might add to explain away unpleasant data. This strikes me as more rationalizing than rationalist.

dthunt 12y ago
Really? Do you actually think that Jaynes is being unreasonable when he assigns ESP a prior that is lower than "has some sort of trick" or some other thing that generally turns out to be the explanatory factor for a magician? He's saying that ESP is an unlikely explanation. He's saying that it is Probably Something Else. The experimental data cannot distinguish them. That's why it's not compelling. It has very little to do with rationalization. It's a terrible test.
- bkcooper 12y ago
  No, clearly the underlying mechanism that he describes is good. However, as he admits in the passage I quote, he is so unconvinced by the possibility of ESP that no tests of this sort could ever convince him. The issue isn't just that naive tests of ESP are easily cheated, either, because you can apply the same logic to more stringently controlled tests. It just seems more honest to me to admit up front in this situation that you cannot be convinced of ESP (give it prior probability of 0) instead of playing these games to essentially shift the "dogmatism" onto the choice of alternative hypotheses and their prior probabilities (which seem chosen to enforce a posterior probability of ESP of ~0.)
  - dthunt 12y ago
    Look. I'll explain it really simple. He's saying it has to be > 0, because he is unwilling to rule out ESP as a logical possibility. If he assigned it 0, no matter how good the experimental design was, and no matter what the test was, he would be unmovable from this position. 0 is forbidden if you want to accept it as a possibility. This is why he says this. He also is being honest about his appraisal of the general likelihood of ESP. It's very low. He doesn't bother to explain how low because it turns out it's IRRELEVANT. You literally have to believe ESP is the most likely explanation among all the usual alternatives ALREADY in order to think it was ESP after ingesting the data, because the data in this test is not EVIDENCE for ESP, because P(E|sort of works ESP) and P(E|one of the assistants wore glasses and Stewart could see some reflections) or whatever your remotely plausible alternative - all look pretty identical. It is not evidence, in the sense that you cannot do 500, 37,100, or a 1 million card guessing attempts in this setup with this level of detail and expect it to shift belief of a rational agent. The ratio between the priors of the usual suspects is going to look the same as your ratio of posteriors between all the hypotheses after the test. In order to convince someone of ESP rationally, you need to demonstrate that it is extremely difficult to cheat under the test conditions, in the sense that P(E|trickery) goes down. Your alternative theory ISN'T the null hypothesis. It's a garden variety non-magical trickster, which exist in great numbers, whereas nobody has yet seen even a single instance of ESP as it is normally meant.
    - 12y ago
loup-vaillant 12y ago
> His overall view of probability is satisfyingly coherent, but I do not consider myself sufficiently expert to assess whether it is meaningfully better than the alternatives. You're probably under-confident. I have read the first two chapters, and they just felt obvious to me. While I understand we could refine probability theory, I think we can say that anything that contradicts it is probably bollocks. > And there are places where I believe he is just wrong, e.g. he seems to reject Bell's inequality and view quantum probability as just another case of limited information. There is a part where he's definitely right, though: the so called "quantum probability" is not a probability at all. No matter how much it looks like a probability, it's something out there in the territory, and probability is in the mind. Besides, the idea that complex numbers (amplitude) could be probabilities is rather ridiculous. And of course, the then popular interpretation of quantum mechanics was crazy: it was either contradicting or denying the very equations that made so good predictions in the first place! Now he could have criticized Many World as well, for it may seem it's a cop-out as well. We have reduced the Born statistics to an anthropic problem, but we haven't solved it yet.

dthunt 12y ago

I very much like the way he lays out the groundwork. It answers fairly directly a lot of criticisms I've seen leveled at probability.

asgard1024 12y ago

Is that a full book? It seems that it has only first 3 chapters. However, I found the other chapters in the directory with the original submission, but they seem to weirdly overlap with content.

thetwiceler 12y ago
Oh, I didn't realize that. Well, the book is Probability Theory: The Logic of Science ET Jaynes 2003 I highly suggest buying it or finding it from your library!
- dthunt 12y ago
  The full text of a draft version is out there, actually. I bought my copy, though. :)