George Monbiot writes: Freedom: who could object? Yet this word is now used to justify a thousand forms of exploitation. Throughout the rightwing press and blogosphere, among thinktanks and governments, the word excuses every assault on the lives of the poor, every form of inequality and intrusion to which the 1% subject us. How did libertarianism, once a noble impulse, become synonymous with injustice?

In the name of freedom – freedom from regulation – the banks were permitted to wreck the economy. In the name of freedom, taxes for the super-rich are cut. In the name of freedom, companies lobby to drop the minimum wage and raise working hours. In the same cause, US insurers lobby Congress to thwart effective public healthcare; the government rips up our planning laws; big business trashes the biosphere. This is the freedom of the powerful to exploit the weak, the rich to exploit the poor.

Rightwing libertarianism recognises few legitimate constraints on the power to act, regardless of the impact on the lives of others. In the UK it is forcefully promoted by groups like the TaxPayers’ Alliance, the Adam Smith Institute, the Institute of Economic Affairs, and Policy Exchange. Their concept of freedom looks to me like nothing but a justification for greed.

So why have we been been so slow to challenge this concept of liberty? I believe that one of the reasons is as follows. The great political conflict of our age – between neocons and the millionaires and corporations they support on one side, and social justice campaigners and environmentalists on the other – has been mischaracterised as a clash between negative and positive freedoms. These freedoms were most clearly defined by Isaiah Berlin in his essay of 1958, Two Concepts of Liberty. It is a work of beauty: reading it is like listening to a gloriously crafted piece of music. I will try not to mangle it too badly.

Put briefly and crudely, negative freedom is the freedom to be or to act without interference from other people. Positive freedom is freedom from inhibition: it’s the power gained by transcending social or psychological constraints. Berlin explained how positive freedom had been abused by tyrannies, particularly by the Soviet Union. It portrayed its brutal governance as the empowerment of the people, who could achieve a higher freedom by subordinating themselves to a collective single will.