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We've reached the maxiumum thread depth, but in brief: Your two comments directly contradict one another. You wrote: > I don't understand how your logic holds

• tptacek 4y ago
  I mean, you can say it, but (a) you're flatly and obviously wrong, and (b) what you're saying is extremely misleading, because there is a lot of research demonstrating heritability of IQ, and none of it establishes genetic determination of IQ. To redefine such an important term flips the status bit from good faith discussion to something else. I'd like to assume good faith! So: reconsider. Later You've extensively edited your comment. In response to those edits: if you look back at my comments, I think you'll see that I haven't made a claim about genetic determinism at all, only that the evidence you've presented doesn't support it.
  • astrange 4y ago
    Nothing can ever establish that intelligence is determined by genetics, because environment always happens to you after genetics do - if it's not affecting your intelligence that just means you've got the wrong environment. (Other factors come into causation when you hold the environment constant, but nobody ever says that!) Or in other words, the reason you're not smarter is because nobody's invented a surgery to make you smarter yet. And the reason you're not less smart is that nobody's hit you over the head with a rock. If either of those scenarios happened, your ancestry wouldn't get to object much.
    • sfblah 4y ago
      Great arguments. Can you give an example of an environment that would enable a cat to play chess as well as me? No? Then there must be a genetic component to IQ.
      • runarberg 4y ago
        Why is your ability to play chess an example of intelligent behavior but not your cat’s ability to jump on furniture? If you want a theory of intelligent to include a notion of general intelligence which can be measured, you must be able to defend which aspects of behavior falls in the category of intelligent, and which not. Playing chess and jumping on furniture both require plenty of cognitive skills, and brain functions to work together and produce a singular outcome, both are goal driven, both takes years of practice, both have varying skill levels. Now the cognitive functions these skills require may both be inherited, you may even find the specific genes which encodes either behavior (and name them the furniture jumping gene and the chess playing gene if you will). However when you assign chess playing as intelligent but not furniture jumping, then you’ve made an arbitrary choice, which you need to justify. (You also have the option of not defining intelligence to begin with; which what I personally would pick). But more importantly, even if you find your justification, you’ve only found one gene of intelligence which inherits, you haven’t found a gene for general intelligence, so you haven’t shown that intelligence is determined by your genes, only the ability to play chess well. Then when you find all the genes for all behavior you consider intelligence, you still haven’t shown that they co-inherit with each other, that is, you haven’t shown that people with the chess playing gene tend to also have the sudoku solving gene, and the IQ test taking gene, etc. For there to be a single general intelligence, and for this general intelligence to be determined by genetics, than this is what is required. Unless of course general intelligence is a real thing and there is a gene for it which allows you to play chess better than others, solve Sudoku faster than others, answer more questions on IQ tests correctly, etc. But this is a rather extraordinary claim, don’t you think?
        • sfblah 4y ago
          I actually like the nuance of your point. I think you're aiming at a certain circularity in the definition of intelligence. Namely, we know that there are a set of cognitive abilities which set certain people apart in society as those who can advance modernity. We find those abilities intriguing, we investigate them, and we measure them and assign them a name. Then, we notice that people who test well for those abilities do well economically and otherwise in society. The whole situation is somewhat tautological. I agree with that reasoning! We defined intelligence the way we do because it "works." If jumping on chairs were what advanced modernity, we would test for that instead. And, that too would "work" because it would surely be a marker for people who were likely to be successful in life. Social sciences aren't going to be able to provide specific answers to your questions in the near term. No, there is no single gene or trait that codes for "intelligence" as we define it. But, that does not mean we can't come up with intelligence tests which correlate strongly with that definition and also correlate strongly with various measures of success in life. Such measures also correlate strongly with society-wide success (measured by a group's progress along the tech tree).