But what is this virtue of political pragmatism? It is not what a dictionary might make you think it is: not a preference for what works in practice over the fine points of theory. The popular distinction between theory and practice is nonsense. It takes a lot of theory to know what will work in practice.

First you need a political philosophy to tell you what outcomes of a policy count as “working”. Should it create wealth? Or should it clean the environment? Or should it achieve something altogether different? Then you need a theory — usually part of economics — to tell you whether or not a policy will have these desired effects.

Of course, many politicians know nothing about philosophy or economics. But such ignorance cannot be what those who boast of their pragmatism have in mind. It would be like a doctor boasting that, being concerned only with curing diseases, he has no interest in medical theory.

Properly to understand the virtue of political pragmatism, we must recognise that policies have two purposes. They are intended not only for the benefit of the nation but also for the benefit of those who promote them. When policies are popular, they can get a politician elected.

“Working” is therefore ambiguous. A policy can benefit the nation (“nwork”) or it can benefit the politician (“pwork”). Pragmatism comes into play when these two ways of working diverge, when the policy that a politician believes will nwork won’t also pwork. Pragmatists prefer policies that pwork.

That is why Tory pragmatists do not like the flat tax policy recently touted by George Osborne. Flat taxes may well nwork — they might cause rapid economic growth that benefits everyone — but the policy is unlikely to pwork: voters just won’t buy it.

Political pragmatism is a curious virtue, being one of the few based on lying. A politician cannot be open about his pragmatism. “I support this policy not because I think it a good idea but only because you will vote for it”; that is not a pragmatic thing to say. Who would vote for someone so unprincipled? But you can do no good in opposition. So goes the standard defence of pragmatic dissembling. Better to sneak into power and then set about doing what you really believe in.

That is what many on the Left vainly hoped Tony Blair was doing in 1997 when he advocated market forces and free enterprise. The good pragmatist is not just a bluffer, but a double-bluffer. He lies not only about what he thinks are the best policies but also about what he intends to do when elected. Virtue unbounded!

Times Recommends

• A new kind of western conservatism
• Georgiana is the wrong role model
• Alaska, where cops don't bother you