I think you have misunderstood at least one thing: P0 and P1 are definitely both true. (They are propositions of the form “there are imaginable states of affairs such that …”.)
Once again, I don’t know very exactly what Harris and Klein have said, so I can’t easily tell what if anything he’s doing with the environmental effects. Are you saying that he thinks there are none? (I am not a big fan of Harris, but I would be astonished if he were being that stupid.) If not, it’s not clear to me what specific “serious error” you think he is making.
Your original comment doesn’t help me here. It observes that there are environmental effects (which, again, surely Harris doesn’t deny) and then jumps straight to saying that “the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”—and I don’t understand where that comes from. I mean, sure, it could well be true that the environmental differences explain everything. But it seems like you jump straight from “there are lots of environmental factors” to “environmental differences probably explain everything” and I just don’t see how you can do that without actually engaging with the details of the available evidence.
(Once again, I’m not saying that you should do that. Only that without doing that, I don’t see how you can reach the conclusion you say you do.)
Of course not, that would be too easy. He does, at some point, explicitly acknowledge that environmental effects exist and are “very important”. And then he proceeds to do nothing with those effects. If you admit that a factor is very important, but then arrive at the same conclusions as someone who believes that the factor has 0 effect, that is still a problem.
I imagine the thinking goes like this. He observes that there are relevant factors X, Y, Z. He notices that Z has a lot of uncertainty, or is hard to work with, or ect. Then he decides that he will look at X and Y in isolation. And then he assumes that whatever conclusions X, Y have lead him to, actually have some bearing on the real world. Depending on Z this may or may not be the case. If it happens that Z really is 0, then you arrive at the correct conclusion, but even then, the path you took to get there is still wrong.
Of course, all of this is very hard to talk about when nobody gives their actual probability estimates (and giving probability estimates is also very hard). In particular this is because the value of P(“inferior genes”) doesn’t seem central to Harris. There is a good chance that I’m misreading him and that his estimate of P(“inferior genes”) is not as high as I assume it to be, and that he really is honestly updating on the environmental differences.
Still, the claim that Harris is making an error seems more likely to me. At least now you better understand what error I’m accusing him of? (By the way, I’m also accusing him of the error pointed out by RamblinDash, but didn’t want to duplicate it).
I think you have misunderstood at least one thing: P0 and P1 are definitely both true. (They are propositions of the form “there are imaginable states of affairs such that …”.)
Once again, I don’t know very exactly what Harris and Klein have said, so I can’t easily tell what if anything he’s doing with the environmental effects. Are you saying that he thinks there are none? (I am not a big fan of Harris, but I would be astonished if he were being that stupid.) If not, it’s not clear to me what specific “serious error” you think he is making.
Your original comment doesn’t help me here. It observes that there are environmental effects (which, again, surely Harris doesn’t deny) and then jumps straight to saying that “the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”—and I don’t understand where that comes from. I mean, sure, it could well be true that the environmental differences explain everything. But it seems like you jump straight from “there are lots of environmental factors” to “environmental differences probably explain everything” and I just don’t see how you can do that without actually engaging with the details of the available evidence.
(Once again, I’m not saying that you should do that. Only that without doing that, I don’t see how you can reach the conclusion you say you do.)
Of course not, that would be too easy. He does, at some point, explicitly acknowledge that environmental effects exist and are “very important”. And then he proceeds to do nothing with those effects. If you admit that a factor is very important, but then arrive at the same conclusions as someone who believes that the factor has 0 effect, that is still a problem.
I imagine the thinking goes like this. He observes that there are relevant factors X, Y, Z. He notices that Z has a lot of uncertainty, or is hard to work with, or ect. Then he decides that he will look at X and Y in isolation. And then he assumes that whatever conclusions X, Y have lead him to, actually have some bearing on the real world. Depending on Z this may or may not be the case. If it happens that Z really is 0, then you arrive at the correct conclusion, but even then, the path you took to get there is still wrong.
Of course, all of this is very hard to talk about when nobody gives their actual probability estimates (and giving probability estimates is also very hard). In particular this is because the value of P(“inferior genes”) doesn’t seem central to Harris. There is a good chance that I’m misreading him and that his estimate of P(“inferior genes”) is not as high as I assume it to be, and that he really is honestly updating on the environmental differences.
Still, the claim that Harris is making an error seems more likely to me. At least now you better understand what error I’m accusing him of? (By the way, I’m also accusing him of the error pointed out by RamblinDash, but didn’t want to duplicate it).