Saletan's series of three articles left me feeling somewhat confused. What follows is an attempt to clarify the question to which he posits an answer.

We should forget about "race" for the moment: first, because "race" has no satisfactorily precise definition (self-identification seems to be the most commonly used), and second, because our emotional reactions to questions involving race tend to be so strong. The really fundamental question is:

(1Q) What is the influence of DNA on intelligence?

I think I know what DNA is, but unfortunately, I have no idea what intelligence is. So we'll have to approximate the question (1Q) above by the more precise, but less fundamental

(1Q') What is the influence of DNA on IQ test results?

Forestalling the inevitable protests: I agree that it seems unlikely that IQ test results can serve as a good measure of intelligence- and therefore I'm skipping the worthy question: "What is the right empirical measure of intelligence?"

A satisfactory answer to (1Q') should be of the form:

(1A') A function assigning to each possible DNA sequence the probability distribution describing the IQ test scores at age 25 of people with the given sequence.

Of course, imprecision remains-in too many ways to list here- but an answer in the form (1A') would still be a huge improvement over any of the answers given by the references provided by Saletan. Is it asking for too much? If IQ test scores are as "genetic" as the "hereditarians" (disclaimer: privately, I have a less polite name for them that begins with "rac" and ends with "ists") would have us believe, then no. Watson himself (in his recent controversial comments) expresses optimism that the genes controlling "intelligence" will be found in no more than 15 years.

Until an answer such as (1A') exists, it's reasonable to consider the existing science of "genetic intelligence" too soft a foundation for social policy.

Perhaps hereditarians (and "race realists") should spend less time fomenting controversy and more time in the lab?

I should have added:

For the hereditarians' to firmly establish their position, they should live up to the standard set by other scientists: make a testable predicton.

At the bare minimum, they should be able to look at the DNA sequences (and no other information) of a group of 10,000 babies, and predict the IQ distribution of these babies at age 25.

When they can do that, I'll be impressed. Until then, they'll have to put up with the name-calling.

What is this? Teach the controversy?

IQ is not some controversial soft measure; it is a very empirically sound predictor of numerous observable phenomena. IQ test scores correlate with academic success, lifetime earnings, artistic abilities, as well a social problems like drug use and crime. Why do you think it is used so often?

Likewise race is not some nebulous, socially defined club. It is a descriptor of cluster of traits in geographical sub-populations of humans. A sub-Saharan African has dark skin and curly hair, and possibly sickle cell. Any one born without those environmental safeguards did not live long enough to pass on their genes.

The concept of race may have become tinged with the horrific use to which it has been put, but, freeing African slaves did not change their race.

You seem to have missed the point.

I'm not criticizing IQ as a "soft measure". I'm asking for an explicit answer to the question: "what impact do genes have on IQ test results?". If you are serious about understanding the real issue, you should want an answer along the lines of my (1A') above.

I don't understand your complaints.

True, you do not criticize IQ as a "soft measure", you deny that IQ is even a valid concept. Or are you arguing that you can use a yardstick to measure leprechauns?

1A' requires that you have 1) a good construct for IQ (i.e. it exists) and 2) a good measure of that construct in order to identify the genes that cause IQ. You are requiring proof that genes can predict something you deny even exists. Only then would you allow that race (another construct that you deny) might correlate with IQ.

I also doubt the “proof” you require is necessary. Persons with dark skin have children with dark skin. Redheads, have redheads. Are you saying that those are not genetically linked traits until we can identify the specific DNA sequence?

Tighten your argument and I won't complain so much!

You are making a simple question too complicated by writing that I claim things I do not claim.

I do not deny that "IQ is a valid concept". I agree that IQ test scores are (duh...) measurable (that's why I'm agreeing to use IQ as a proxy for "intelligence"- a concept which must be made precise in some way before it can be measured).

You really believe that it's too much to ask for the genetic mechanism explaining any given hereditary trait? If you really understood what was going on with IQ test results, you'd be able to answer question (1A'). That's the only important point I'm making- ignore the name-calling if you want.

And I am ignoring the concept of "race" in this post: though in fact you CAN tell if someone is a redhead (skin color is more complicated, but you can give an answer along the lines of my (1A') for that too) by looking at their DNA. Whatever the answer is for IQ test results, it will be more complicated than for hair color and skin color (for which we have a pretty good understanding). But the point is that whatever conclusions about "race and intelligence" there are to be drawn would follow from a really satisfactory answer to (1A'), so there's no need to ask explicit questions about "race" (or even to spend time defining what we mean by "race").

By the way, you ask me to "tighten my argument", but refer to "IQ" (an abstraction) instead of the more concrete "IQ test results at age 25" that appears in my (1A'). How ironic.

A better objection to my original post is that one can come up with lots of "answers" of the form (1A') that don't really deepen our understanding of the influence of genes on IQ scores. For example, one might attach a normal distribution with mean 100 and standard deviation 10 to *every* possible human DNA sequence; for large (randomly chosen) groups of people this will predict the (setwise) IQ scores pretty well.

The point is that the heriditarian case is strengthened only by an answer that subdivides all possible DNA sequences and gives, for each part of the subdivision, a probability distribution with small variance.

I tend to doubt that the variances can be made very small (though surely there exist subdivisions which improve the variance of 10 given by the "trivial" answer above). My main objective was to outline the program the heriditarians would have to complete in order to convince me of their case.

SGriffeth:

they should live up to the standard set by other scientists: make a testable prediction.

I have asked for the same level of rigour here. All I got in return was bluster. I will agree that IQ testing is not pseudo-science and that if you are going to measure intelligence then measuring abstract reasoning in a culturally unbiased way is a definite start. (Intelligence is currently such a vague term it beggars belief.) Somebody in another post mentioned Karl Popper.

Logically, no number of positive outcomes at the level of experimental testing can confirm a scientific theory, but a single counterexample is logically decisive: it shows the theory, from which the implication is derived, to be false. Popper's account of the logical asymmetry between verification and falsifiability lies at the heart of his philosophy of science.

We must ask ourselves. Is the racial 'theory' of IQ falsifiable? Also, is it useful? Can it make useful predictions. A number of theoreticians and statisticians (I refuse to call them scientists and I make no apologies for it) have claimed to have repeatedly verified their 'theory'. But what is the experiment we can perform to falsify their claim? There is none at the present because their 'theory' is far too immature. Race needs to be clearly defined. Intelligence the same. And finally the racial IQ 'theory' must be shown scientifically how the two are correlated.

I will not subscribe to anything less than the list of genes involved, a universally agreed upon model of intelligence, a system that completely describes how the genes list affect intelligence and a full, plausible and falsifiable account of how IQ tests measure the agreed upon concept of intelligence and preferably only that and with all that information we should be able to look at the dna sequence of an foetus and say, "Age 25, IQ blah".

I am not a bleeding heart liberal. I assuredly will accept the truth no matter how abhorrent it is if the science is genuine.

Yes, thanks for pointing me to the link. I hadn't read your earlier post. We seem to agree for the most part.