Leading article: An unworthy intervention

As one of the discoverers of the DNA double-helix, James Watson's status as a brilliant scientist is beyond challenge. But what are most certainly not beyond challenge are his recently voiced theories on race and intelligence. Indeed, it is in the interests of science and humanity that these theories are challenged and exposed for the nonsense they are.

Dr Watson stated at the weekend that he is "inherently gloomy about the prospect of Africa... because all our social policies are based on the fact that their intelligence is the same as ours - whereas all the testing says not really". He went on to argue that although one hopes that everyone, regardless of ethnicity, has equal powers of reason "people who have to deal with black employees find this not true".

Let us unpick the scientific basis for these assertions. What is the "testing" to which Dr Watson refers? Dr Watson was presumably referring to the research from the 1990s which purported to show that black Americans generally have a lower IQ than white Americans. But IQ testing is a highly dubious way to determine intelligence. And the idea that there is some kind of strong hereditary genetic factor behind a person's IQ score is by no means proven. Dr Watson is even more culpable in the conclusions he draws from this flawed research. Even if the science was solid it would be an unjustifiable extrapolation to talk of "Africans" or "black employees"having lower intelligence as a result.

So much for the science. But what of the ethics of such assertions? Dr Watson himself may not be a racist. And it is a charge he denies today in this newspaper. But what is beyond doubt is that his words recall the discredited science of social Darwinism and racial eugenics. They also give succour to racists. As such they were irresponsible – andunworthy of so eminent a scientist.

With all this in mind it is understandable that London's Science Museum cancelled Dr Watson's scheduled talk to promote his new book this week. It is understandable - but wrong. It would have been better to allow him to talk and then to allow other scientists to discredit his theory in open debate. The organisers of Dr Watson's other talks should ensure they go ahead.

Curtailing free debate is almost always a mistake. Allowing scientists and individuals to air their theories openly does not validate them. On the contrary it allows them to be refuted. Suppressing views simply drives them underground. When this is done with relation to abhorrent views on race, the effect is doubly pernicious. Dr Watson has had his say. Now let us see how well his views stand up to the public scrutiny of his scientific peers.