Comment on Philosophical differences

Wed, 17 Jun 2015 20:39:32 GMT

...So, I found it ludicrous to call the reverse Sobel sequence false. I still basically feel that way after reading the article again, though I should say that the author gets around to a better account of the situation on page 12 of 29 (and on close inspection, Moss doesn't really follow this by heading back to the same zombie-infested cul-de-sac. Not quite.) If the following statements come from different speakers, the second seems socially rude:

(3a) If Sophie had gone to the parade and been stuck behind a tall person, she would not have seen Pedro.

(3b) #But if Sophie had gone to the parade, she would have seen Pedro.

Since the author sometimes seems to treat these as made by one speaker, and the article is nominally about counterfactuals, I assume that both statements come from the same world-model or causal graph. I also assume that each comes from a human being, and not a logician or Omega, and thus we should take each as asserting a high probability. (The article only briefly considers someone saying, "Suppose that Sophie might not see Pedro, but that she will see Pedro," which I don't think we could make sense of without reading an explicitly conditional probability into the first half of the premise.) So with two different speakers, I see two credible ways to read (3b):

A. 'Shut up.'

B. 'You are altering the wrong node.' (Because, eg, 'Had Sophie gone to the parade, she would have looked for a good place to see it.')

If it's just B, then politeness would require doing more to rule out A and maybe explain why the speaker doesn't care about the first counterfactual. Note that reversing their order (that is to say, un-reversing it) would give us what sounds like an invitation to keep talking. As Moss says, the "reply may be a non sequitur, perhaps even a little annoying." But it doesn't read as contempt or dismissal.

In the unlikely event that (3) has only one speaker and she isn't disagreeing with anyone, then we have:

C. 'The answer you get depends almost entirely on the question you ask. The whole point of counterfactuals is to screen off the causes that would ordinarily determine the (probability of the) node you change. Suppose we compute different answers when we ask, "What would the founding fathers say if they were alive today?" and "What would the founding fathers say if they had lived in our time?" Then the person who chooses the question probably knows the answer they want. Peripherally, I assert that the chance of Sophie getting stuck behind tall people would be too small for me to bother qualifying my statement.'

The main point of C seems obviously true as soon as I think about doing surgery on a causal graph. We can assume both counterfactuals are also true. (3) still seems "infelicitous" because as a rule of thumb it seems like a terrible way to express C, but that depends on the audience. If we rule out C as a reading, then the speaker's statements could still be true, so I would probably call them "epistemically responsible", but her goals would make no sense. She would sound like a more philosophical Gollum.

Now if you're saying that C does not seem immediately clear to you when you think about doing counterfactual surgery, I will withdraw my original criticism. I would have many new criticisms, like the author assuming intuitions I may not share and analyzing common language while barely mentioning society or motive. There's also what reads to me as mock-formalism, adding nothing to Pearl while distracting from the issues at hand. But the issue would at least warrant discussion, and I'd have to consider whether checking for references was a good test for me apply to the article.

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