This reads strongly of someone who is desperate to not accept inherent limitations in human beings as physical embodied agents with a support structure designed and quantified by genetics and physics.
Were this a different discussion, they'd need to involve ideas of a non corporeal soul or equivalent to explain their beliefs.
I think it's pretty funny that no matter how straightforward the methodological critiques of 90s-vintage twin studies are, they always elicit responses as if the critiques were metaphysical, rather than (for instance) deliberately excluding the dizygotic twin control group from MISTRA because it revealed the studies findings were just noise.
The truth is, for these kinds of studies, the whole enterprise might as well be metaphysical; people saying these kinds of things have formed a religious conviction about the heritability of behavioral traits, and their real objection is that science continues to be done on the topic at all. Ironic, given the frequency with which they complain that this science is suppressed.
(I too have a near-religious conviction about this subject, though in a different direction; I do not, however, pretend that conviction is itself a methodological critique!)
In my mind, the bigger issue with twin studies trying to show that (say) IQ is highly genetic is that humans do not reproduce by cloning. And regression toward the mean is very much a thing for heritable traits.
In other words - Junior should not be presumed to be smarter, fitter, more deserving, or destined for success, just because his parents did well. No matter how attractive that conclusion might sound, to people who consider themselves to be the "better" sort.
That doesn't sound like a problem with twin studies exploring the degree to which IQ is genetic, that sounds like a problem with people treating aggregate tendencies and associations as a basis for individual discrimination.
The problem is most people's zealous desire to read socially self-serving conclusions into any data they can find on such subjects. And when they really like the Q.E.D. punchline, humans have very low standards for the "logic" used to reach it.
iq is "polygenetic" with the consensus estimates at 50-80% based on genes
success has components of luck as in "right place, right time" for someone with the right qualities and connections, and many of the very successful are quick to admit this
I am a 3rd generation machinist along the paternal line, and although the machines I operate are in expensive labs, those my father and grandfather operated were probably just as challenging. Engineering also seems to often run in the family. How much is nature and nuture? "It varies" is a safe response
Whoah, no, there is definitely not a consensus for 50-80%, and most of what's being published now refutes the 80% end of that range --- the 80% estimates come from underpowered studies like MISTRA that improperly assumed independent environments for twins reared apart.
The truth is, for these kinds of studies, the whole enterprise might as well be metaphysical; people saying these kinds of things have formed a religious conviction about the heritability of behavioral traits, and their real objection is that science continues to be done on the topic at all. Ironic, given the frequency with which they complain that this science is suppressed.
(I too have a near-religious conviction about this subject, though in a different direction; I do not, however, pretend that conviction is itself a methodological critique!)
Related, from last year: https://news.ycombinator.com/item?id=42200209
In other words - Junior should not be presumed to be smarter, fitter, more deserving, or destined for success, just because his parents did well. No matter how attractive that conclusion might sound, to people who consider themselves to be the "better" sort.
The problem is most people's zealous desire to read socially self-serving conclusions into any data they can find on such subjects. And when they really like the Q.E.D. punchline, humans have very low standards for the "logic" used to reach it.
success has components of luck as in "right place, right time" for someone with the right qualities and connections, and many of the very successful are quick to admit this
I am a 3rd generation machinist along the paternal line, and although the machines I operate are in expensive labs, those my father and grandfather operated were probably just as challenging. Engineering also seems to often run in the family. How much is nature and nuture? "It varies" is a safe response