“Descartes … nowhere integrates his conception of the human mind into a theoretical structure … justifying the fundamental … equality of men in society. Here Hobbes came closer with his path-breaking concept of a general equality in a “state of nature,” an invaluable flexible analytical tool…:

“When all is reckoned together,’ Hobbes affirms … the differences between men in their faculties of mind and body are ‘not so considerable as that one man can thereupon claim to himself any benefit to which another may not pretend as well as he.’ Roughly speaking, men are equal in terms of their power and even more equal in their minds than their bodies. If one is stronger, another may be more cunning, and ‘such is the nature of men,’ observes Hobbes,’that howsoever they may acknowledge many others to be more witty, or more eloquent, or more learned, yet they will hardly believe there be many so wise as themselves.’ This is because we know the detail of our own thoughts, he suggests, but mostly oversimplify the reasoning of others:’but this proveth rather that men are in that point equal, than unequal. ‘From this equality of ability,’ contends Hobbes, ‘ariseth equality of hope in the attaining of our ends.”

—Johathan Israel, Enlightenment Contested, p.552

The interesting thing about this debate is that it touches on public policy. Perhaps we cannot link intelligence levels with discrete genetic groups with any scientific certainty but we equally cannot unlink them. However the default position, as far as current public policy is often made on just that assumption. Differing levels of achievement are held as a priori evidence of racism.

Do you feel that placing the burden of proof upon racists is a bad thing?

Yep, because that is the whole point about the question of heritability.

“but not be able to explain how it works; to me that wouldn’t be a scientifically very convincing or interesting answer”

Why not convincing? If we find it is heritable how could questions of mechanism have any bearing in how convincing that finding is? As for interesting, well horses for courses I guess.

Even if “IQ” is heritable—even 100 percent heritable—heredity is a dynamic process.

If a high “IQ” really is a trait that is adaptive for the survival of our species (which is quite dubious actually) it will spread very rapidly, both by being manipulated (education, games, culture, sexual selection and the like) even within a few generations, as well as by the circumstance of those who are less adapted dying before puberty or otherwise failing to reproduce themselves (according to the theory of evolution).

It will spread by sexual selection alone, if it is perceived as culturally desirable.

My own hunch is that people who think they have a high “IQ” may have an inflated sense of their own worth. As for our species’ requirement for a hi-tech society in order to survive, along with the nerdy types needed to maintain it—the opposite might be true.

But there’s a difference, isn’t there, between doing research and claiming we are currently in a position to say anything definite?

talk about a scientific explanation of IQ, let alone it being hereditary, is currently absolute and total bunk

and you followed this with a set of considerations about our lack of understanding of the physiological mechanisms which underly these results which, if they were valid, would apply just as well to almost any current or past research in experimental psychology. So are you claiming that all psychology is “absolute and total bunk”?

without recourse to (future) neuroscience you would only be able to point at the input and the output and their relation, but not be able to explain how it works; to me that wouldn’t be a scientifically very convincing or interesting answer, especially since we’re talking about something as complex as the brain

engels, I don’t see how I’m contradicting myself here, since I am convinced that, while neuroscience is comparatively speaking still in its infancy and its explanatory power is still limited, it will progressively be able to validate, refute and/or substitute the vocabulary of psychology – until then we should regard the concepts of psychology (and philosophy) with caution

I call the brain a black box, because, as I have pointed out above, we currently don’t really know a lot about its inner workings, especially when it comes to higher-order brain functions such as language, mathematical and social skills. We don’t have a scientific basis for explaining phenomena such as memory, consciousness, free will, perception of other minds, thought processes and creativity. Considering the fact that we still know so little about the brain,all such discussions are on the level of pre-scientific medicine… Thus all such discussions are highly speculative, mostly unscientific and prone to abuse by parties with ulterior motives.

The rest of your points have been made by Shalizi, and better.

I still don’t see what neuroscience has to do with anything. Could you envisage some finding in neuroscience that could undermine a finding of 100% heritability of some behaviour?

Yes, sure we can mendel away on the simpler traits, like eye or skin color, but these are all:

1.) simple to define
2.) simple to observe
3.) not dynamic i.e. they don’t change much or at all during the lifetime of a subject

While the intelligence/IQ is

1.) hard to define
2.) hard to test and controversial
3.) inherently dynamic
4.) interactive and culturally variable

Do we really know what we’re talking about when we talk about intelligence? If you keep a, for the sake of argument, genetically very intelligent baby locked in a dark room long enough, it will end up stupid. If somebody drives a steel bolt through certain brain regions, you might be lucky and redevelop your respective skills in another part of the brain. Even during a lifetime people can experience changes in their mental faculties due to lack or abundance of stimuli, emotional state, physical health etc. Then you have people who are professors for whatnot and regarded by everybody as intelligent, but have no spatial awareness or mathematical skills at all, so that they wouldn’t do too well on a standard IQ test.

All of this and other things lead me to believe that without a thorough understanding of the brain’s workings, we should not talk about intelligence as if it were an objective or even scientific measure.