There’s nothing selfish about capitalism. Like every economic model, it is a matrix within which individual actors can behave morally or immorally. But here’s the thing: no one has yet come up with a system that rewards decent behaviour to the same extent.

In an open market based on property rights and free contract, you become wealthy by offering an honest service to others.  I am typing these words on a machine developed by the late Steve Jobs. He gained from the exchange (adding fractionally to his net wealth) and so did I (adding to my convenience).

Under the various forms of corporatism tried by fascist and socialist regimes, by contrast, someone else – generally a state official – gets to allocate the goodies, guaranteeing favouritism and corruption.

Greed – that is, the desire for material possessions – is not a product of markets, but a product of a human genome evolved in a competitive environment. Capitalism harnesses greed to socially productive ends. The way to become rich in a free economy is to give others what they want, not to suck up to those in power.

We’re not arguing about whether generosity and charity are laudable. We’re arguing about whether big government encourages them.

I know plenty of Lefties who put in long hours on behalf of the disadvantaged. Equally, though, I’ve noticed a trend which seems much more common on the Left than on the Right: the tendency to elevate the moralistic (holding the right opinions) over the moral (doing the right thing).

The most striking thing about this attitude is its narcissism. Evil, having lost the meaning attributed to it by the monotheistic religions, has instead come to mean ‘someone who disagrees with me’.

Once you’ve established your fundamental decency by signalling your disapproval of the right things, why go any further? Once you’ve called for tax rises, why give to charity?

It can’t be repeated too often: when you give to good causes, you are making a moral choice. When the government takes an equivalent sum from you in taxation and spends it on your behalf, you are not. The argument for state involvement is a practical, not an ethical, one.

It’s true that capitalism is often debased by lobbying, cronyism and subsidy. The most outrageous – and, indeed, unethical – distortion of the capitalist system in recent years was the decision to bail out the banks. Quite apart from rewarding failure (the precise opposite of making money by providing a service), it transferred wealth from the poor to the rich.