It's become a clich'' that the Occupy movement has few good ideas for improving the economy. But it is not alone. The same can be said for the Tory right, for example:

- the call to relax employment protection, despite the absence of any empirical or theoretical evidence that doing so would increase employment.

- a demand to scrap the youth minimum wage, even though this would, at best, make only a small dent in unemployment.

- a demand (pdf) to scrap the 50p tax rate on the grounds that it might eventually deter work and entrepreneurship, even though there's no evidence yet for such effects*.

What interests me here is: why should the standard of rightist argument be so low - almost wilfully ignorant of opposing evidence? Here are five theories:

1. Diminishing returns have set in. Back in the 70s, one could argue with at least some plausibility that strong workers' rights and high taxes were squeezing profits and deterring effort. By now, though, the effective policies in the neoliberal barrel have been taken, leaving its advocates to scrape the bottom.

2. Inequality breeds arrogance. The rich and their lackeys feel so smug and that they believe they don't even have to try to cloak their self-interest in the disguise of economic efficiency.

3. An anti-scientific culture. Why bother with awkward, messy, statistical evidence when your own prejudice and ego tell you all you need? This philistinistic attitude is perpetuated by the BBC, with its absurd tendency to present the bar-room talk of business people as serious proposals to raise economic growth.

4. The politicians' syllogism: 'Something must be done. This is something. Therefore this must be done.' Policies such as the ones above don't arise from a thorough investigation of the evidence, but rather from a desire to get growth going again, combined with (1) and (3).

5. There's a race to the bottom. If you believe that the best your opponents can do is advocate a Robin Hood tax or claim that tax evasion caused the world economic crisis, then you'll have no incentive to think hard and well - any more than Man United would need to put out their strongest team if they were drawn against Anstey Nomads third XI in the Cup. A lack of competition produces low standards.

I've said before that ability is endogenous, and so the successful don't deserve credit. But maybe a lack of ability is endogenous as well, so we shouldn't blame the right for their apparent stupidity.