3 ms·

The beginning of the article is an excellent (though conventional) introduction to Bayes and Bayesian updating, but what I found original and have never seen ex

by FabHK 4y ago

The beginning of the article is an excellent (though conventional) introduction to Bayes and Bayesian updating, but what I found original and have never seen expressed so clearly were the remarks about dishonest discussion tactics, especially the first one: Formulate a vague hypothesis H1 so broad that it is not extremely unlikely (thus has non-negligible prior, P(H1) > 0), then in the updating step sneakily introduce a much more specific hypothesis H1’ that is far less likely a priori, but that yields a high probability for the evidence P(E|H1’). If the audience doesn’t notice the bait and switch, it’ll come away with the impression that the evidence strongly supports H1/H1’ vis-à-vis H0, when it actually doesn’t. Reminiscent of the Motte and Bailey fallacy. https://en.m.wikipedia.org/wiki/Motte-and-bailey_fallacy https://en.m.wikipedia.org/wiki/Motte-and-bailey_fallacy

mistermann 4y ago
It's even more complicated than that though: "dishonest discussion tactics" suggests that the person is doing it with fully conscious awareness and intent, but this is far from a safe assumption - and, it isn't a simple binary "is or is not", and it isn't only the usual suspects who commit this technique.
- simonh 4y ago
  Maybe so, but ultimately it's up to us to take responsibility for the techniques we use in argumentation. I would agree that it's not generally a good idea to try to use an attack on the rhetorical techniques someone uses in order to win an argument. It's best to politely find a way to challenge their argument without attacking them personally for the way they put their case.
  - mistermann 4y ago
    A very reasonable take...but I wonder if there might be a substantially more optimal approach, that is possible.
pc86 4y ago
Maybe it's just my liberal arts education but discussions like this and comments like "hypothesis H1’ ... that yields a high probability for the evidence P(E|H1’)" or "evidence strongly supports H1/H1’ vis-à-vis H0" mean absolutely nothing to me without a concrete, real-world example of what H1, H1', and H0 are.
- time_to_smile 4y ago
  It's not the presence of a liberal arts education, it's the absence of a mathematical one (and technically mathematics is one of the 'liberal arts'). I have a liberal arts background, but also a statistics background and reading this is no problem for me. Reading and thinking mathematically is a literacy the same way reading sheet music is a type of literacy. Just like there are degrees of literacy for reading and writing same with these disciplines. Some people can't read sheet music at all. I can name the notes when reading sheet music, and know where they are on a piano, but, unlike many musician friends, I can't "hear the music" when I read. Similarly it takes time and practice to "read mathematics". To someone with no practice the notation appears as scribbles. A more experienced mathematician will pause and work through what's happening. At a certain point, you start to experience the same "hearing the music" with mathematical writing.
- defen 4y ago
  > Formulate a vague hypothesis H1 so broad that it is not extremely unlikely (thus has non-negligible prior, P(H1) > 0), then in the updating step sneakily introduce a much more specific hypothesis H1’ that is far less likely a priori, but that yields a high probability for the evidence P(E|H1’). H0 is "the lottery is fair" (null hypothesis). H1 is "somebody rigged the lottery". It's not outrageously unlikely, it's happened many times before and it's something people can easily understand, and it's not specific about the details. So maybe someone would say "Without knowing more, I think there's a 1% chance that happened". H1’ is "The lottery is rigged by a cult that worships the multiples of {9}" - This is the sneaky step. If it weren't such an obviously outrageous example, you might not notice that this specific hypothesis is very unlikely. However, H1’ perfectly predicts the evidence that we did observe! So basically, if you plug in the numbers, without adjusting for the fact that H1’ does not have a 1% chance of being true, you turn "I think there's a 1% chance someone rigged the lottery" into "The lottery was almost certainly rigged - 99.9997% chance!"

by FabHK 4y ago

mistermann 4y ago

It's even more complicated than that though: "dishonest discussion tactics" suggests that the person is doing it with fully conscious awareness and intent, but this is far from a safe assumption - and, it isn't a simple binary "is or is not", and it isn't only the usual suspects who commit this technique.

simonh 4y ago
Maybe so, but ultimately it's up to us to take responsibility for the techniques we use in argumentation. I would agree that it's not generally a good idea to try to use an attack on the rhetorical techniques someone uses in order to win an argument. It's best to politely find a way to challenge their argument without attacking them personally for the way they put their case.
- mistermann 4y ago
  A very reasonable take...but I wonder if there might be a substantially more optimal approach, that is possible.

pc86 4y ago

Maybe it's just my liberal arts education but discussions like this and comments like "hypothesis H1’ ... that yields a high probability for the evidence P(E|H1’)" or "evidence strongly supports H1/H1’ vis-à-vis H0" mean absolutely nothing to me without a concrete, real-world example of what H1, H1', and H0 are.

time_to_smile 4y ago
It's not the presence of a liberal arts education, it's the absence of a mathematical one (and technically mathematics is one of the 'liberal arts'). I have a liberal arts background, but also a statistics background and reading this is no problem for me. Reading and thinking mathematically is a literacy the same way reading sheet music is a type of literacy. Just like there are degrees of literacy for reading and writing same with these disciplines. Some people can't read sheet music at all. I can name the notes when reading sheet music, and know where they are on a piano, but, unlike many musician friends, I can't "hear the music" when I read. Similarly it takes time and practice to "read mathematics". To someone with no practice the notation appears as scribbles. A more experienced mathematician will pause and work through what's happening. At a certain point, you start to experience the same "hearing the music" with mathematical writing.
defen 4y ago
> Formulate a vague hypothesis H1 so broad that it is not extremely unlikely (thus has non-negligible prior, P(H1) > 0), then in the updating step sneakily introduce a much more specific hypothesis H1’ that is far less likely a priori, but that yields a high probability for the evidence P(E|H1’). H0 is "the lottery is fair" (null hypothesis). H1 is "somebody rigged the lottery". It's not outrageously unlikely, it's happened many times before and it's something people can easily understand, and it's not specific about the details. So maybe someone would say "Without knowing more, I think there's a 1% chance that happened". H1’ is "The lottery is rigged by a cult that worships the multiples of {9}" - This is the sneaky step. If it weren't such an obviously outrageous example, you might not notice that this specific hypothesis is very unlikely. However, H1’ perfectly predicts the evidence that we did observe! So basically, if you plug in the numbers, without adjusting for the fact that H1’ does not have a 1% chance of being true, you turn "I think there's a 1% chance someone rigged the lottery" into "The lottery was almost certainly rigged - 99.9997% chance!"