Reading Jonathan Freedland's piece on the soft left's dalliance with eugenics reminded me of the argument about whether town councils should say prayers at their meetings. What links these two different issues is that both sides appeal to an illusory certainty.

Take eugenics first. On the one side, eugenicists were certain that the state had the power to affect the composition of the race. Reading Sidney Webb's The Decline of the Birth Rate (pdf) one is struck not only by the vile racism - he frets about the country 'falling to the Irish and the Jews' - but also by the utter absence of any doubt about the state's competence.

On the other side, though, stands a claim that people have a right to have children. And rights - being entitlements - are things we possess with certainty. Freedland writes:

What was missing was any value placed on individual freedom, even the most basic freedom of a human being to have a child. The middle class and privileged felt quite ready to remove that right from those they deemed unworthy of it.

We have here a clash of certainties - the certainty of state competence versus the certainty that a right exists.

Which is what we have in the Bideford town council case. The protagonists claim that this is a clash of rights, of certainties. Clive Bone claimed that prayers violated his right to be free of religion, whilst Eric Pickles said: "Public authorities - be it Parliament or a parish council - should have the right to say prayers before meetings if they wish."

However, in both cases the argument should not be about certainties, but rather about mundane competence.

The argument against eugenics is not that people have a right to have children. It's not clear that they do. John Stuart Mill thought they didn't. He wrote:

To bring a child into existence without a fair prospect of being able, not only to provide food for its body, but instruction and training for its mind, is a moral crime.

And at least one recent book on human rights is almost silent on whether this 'right exists.

Instead, the argument is simply that the state is just not competent to adjudicate who should have children; if eugenicists ruled the world, there'd be no jazz or blues music and not just because of the colour of the musicians' skins.

Similarly, in the Bideford case, the argument against saying prayers at council meetings is not one of rights, but, again, one of competence. Quite simply, council meetings should be devoted to council business, not to prayer. In fairness, this was how the judge ruled - not that either side seems to care about that.

The fact that these two cases are separated by 80 years is depressing. It shows that experience doesn't teach us that our knowledge of public life and moral affairs is fragile and partial. Instead, we see the same appeal to a non-existent certainty in different guises.