I have pointed out before that rightists are prone to a rhetorical trick which I've called "small truths, big errors" - a tendency to use a small factual claim to obfuscate a bigger issue. Tim Worstall gives us an example of this today. In replying to Will Hutton's call for efforts to get more poor kids into top universities, he points out that intelligence is heritable, and so we'd expect some inequality in unversity admissions.

I'll concede this. But this misses two big points.

First, heritability of pure academic ability probably doesn't explain all of the inequality of which Will complains. Rich parents can increase their chances of getting their kids into top universities not just by giving them the right genes, but by buying houses in the best school catchment areas or by providing more cultural capital.

One big fact suggests that such non-genetic bequests matter. It's that greater inequality of income is associated with greater inequality of opportunity. As a World Bank report says (pdf):

The data reveal a positive correlation between inequality of opportunities and income inequality. Countries with a higher degree of income inequality are also characterized by greater inequality of opportunity.

This is consistent with Will's main point, that increasing equality of access to university requires "mobilising against inequality in all its manifestations."

Secondly, even if Tim were wholly correct to imply that heritability of ability explains all the inequality of access to university, it would not follow that such a situation was fair. In fact, from the point of view of luck egalitarianism it is not. This theory says that inequalities are unacceptable insofar as they arise from factors beyond an individual's control. And, obviously, a person's genes are beyond their control.

Of course, luck egalitarians would not argue that people should be accepted into universities regardless of ability. But they would argue that they shouldn't suffer (much) because of their inherited lack of ability. Herein lies one argument for a redistributive tax and benefit system; it helps to equals out the effects of the genetic lottery.

Indeed, luck egalitarianism predicts that redistribution should have increased since the 1970s, because since then the penalty for inability has increased. A mix of globalization, deindustrialization and technical change has reduced demand for unskilled labour, with the result that their relative pay and chances of getting a job have worsened. But this has not happened.

My point here is not merely to criticize Tim. It's broader than that. What I'm saying is that you cannot point to the heritability of ability (howsoever defined) to defend inequality. To do that, you must also argue against luck egalitarianism.