What has capitalism ever done for women? Not much, you might think. Half the top companies in Britain still have all-male boards, 19 chief executives out of 20 are men, and so are two managers out of three. Women are good at flying planes, but 99% of pilots are men. Women with equal qualifications have to work six hours to get what a man will earn in five, and still they run a much greater risk of losing their jobs. Unfair or what?
On the other hand, the life of women was not a breeze before capitalism came along; and as for socialism … in your dreams. Capitalism can lead to massive inequalities of wealth, but the idea of equal rights is built into the very notion of capitalist open markets. Maybe it is no accident that the century of triumphant capitalism was a century of militant feminism too. Perhaps capitalism is really a girl's best friend.
Marx and Engels had much the same idea. They were not starry-eyed about free markets, but they loved the spectacle of capitalism pulling down the barriers of feudal prejudice. Capitalists, as the Communist Manifesto points out, have no interest in discriminating against women: workers are workers, the more the merrier, and wages are wages, as low as may be. But Engels soon realised that, if capitalism was destined to abolish sexual inequality, it was taking its time. He became intrigued by the idea of "primitive communism", and liked to imagine ancient wandering tribes where women cared for children in common, while men had to beg for their favours. In the age of the hunter-gatherer, it seems, sisterhood was powerful and motherhood ruled. But agricultural settlement and the rise of private property put an end to all that: men became obsessed with the danger of leaving the fruits of their labour to children who might not be theirs, and they built the prison house of monogamous marriage and locked up their women inside. Hence the "world historical defeat of the female sex", as Engels called it – a calamity still unavenged after ten thousand years.
Paul Seabright does not mention Marx or Engels, but in his witty, informative and cogent new book he picks up the story of women and capitalism where they left off. Seabright is an economist by trade, though some of his colleagues regard him as an oddball, even a miscreant. His special subject is what he calls the "natural history of economic life", or how Homo sapiens evolved into Homo economicus, and his line is that modern market economies are not the natural outcome of historical progress, but the improbable upshot of a series of accidents. He is not one of those fundamentalists who see markets as immaculate machines that will run perfectly as long as they are shielded from outside interference. But he is not an Occupy radical either, seeing nothing in markets but greed and law-of-the-jungle anarchy. Markets as he sees them are magnificent institutions, drawing on vast and intricate reserves of mutual trust. In economics as in sport, competition presupposes an agreed set of rules. "Everyday life is much stranger than we imagine," as Seabright put it in 2004, in a celebrated book called The Company of Strangers. Ten thousand years ago, we roamed through the forests in small family groups, "violent, mobile and intensely suspicious". But today we trust for our daily needs to immense networks of convention, assumption and co-operation that none of us can understand or control. The strange thing about modern markets is not that they sometimes go wrong, but that they ever work at all.
I can see what he means. Three weeks ago there was a derelict pool-hall across the road from my flat; in a matter of days a swarm of builders transformed it into an acre of gleaming retail space, then the massed staff of SportsDirect filled it with clothes and shoes in myriad shapes and sizes, and in no time I was kitted out in a cool green and black hoodie with built-in earphones that cost me less than a pint of beer. My flutter may have been foolish, but it would not have been possible without the contributions of hundreds of thousands of people of whom I know nothing, all getting on with their own lives and doing their own thing. I know that it's the economy, stupid, but it feels more like the power formerly known as magic.
Why should a system that can provide me with a hoodie wired for sound fail to deliver when it comes to sexual equality? The easy explanation – that women are less efficient than men – does not stand up to scrutiny. Seabright surveys the results of psychometric tests and concludes that the overall differences between men and women are far too small to account for the divergence in their economic prospects. For comparison, he considers the economic consequences of height. Tall people are, on the whole, better paid than short people, just as men are better paid than women. But there is apparently a real correlation between height and exploitable talent, and workers of different heights will face the same economic prospects if they are equal in other respects. Sex is different – but why? If capitalist practice conformed to capitalist theory, then a canny entrepreneur would take on women instead of men until scarcity pushed up their wages. How can the market be so dumb?
Like Engels, Seabright seeks an explanation in pre-history, but with Darwinian knobs on. Our stone-age ancestors would not have been ancestors at all if they had not managed to get their heads round a few hard problems in social co-operation. They could not be content with finding a mate and making a viable baby; they also had to ensure that it would be nursed and nurtured through childhood so that it could breed again in its turn. But the problems facing aspiring dads were not quite the same as those facing aspiring mums. A woman would not, on the whole, have any difficulty finding someone to make her pregnant, whereas every man ran a significant risk of being a genetic dead end. So men needed to "advertise" – they had to impress women with their ability to protect and provide. Women advertised too, to assure men of their commitment to childcare. The prize of parenthood, in short, went to those who had not only the best capacities, but the best PR as well. And our 21st-century brains have been built according to DNA blueprints passed down from these stone-age self-publicists. We are lumbered with male and female emotions that date back, as Seabright puts it, to the days when sex was "not a matter of lifestyle but of life and death".
But Seabright is no neuromaniac: our outdated emotions are facts we need to live with rather than laws we have to obey. We sexual gods and domestic goddesses are not automata driven by basic instincts, but dupes of the obsolete publicity machines in our heads. When men try to big up their stamina, or women make a display of conscientious self-sacrifice, they are falling into a "signalling trap" that they could avoid if they wanted to. And employers with a bit of imagination need not be taken in either. They can train themselves to see that the hero of labour who makes a point of working long hours is really engaged in a form of wasteful display, the human equivalent of a peacock's tail, and that the reticent woman need not care any less about her work because of her childcare obligations. And they might well find that male employees would be more productive if they could be induced to take career breaks at least as often as women. Employers who fall for the signalling trap are not only doing women an injustice, but missing a commercial opportunity as well. All we need do, if we are worried about sexual inequality, is give capitalism a chance.
Sturdy old pessimists will not be persuaded, of course. By jumping straight from the stone age to the 21st century Seabright has managed to overlook more than a few sources of persistent injustice. And, like many economists, he is in danger of imagining that life ends when we stop work. But his confidence is beguiling, a glimmer of light in a gloomy old world.
• Jonathan Rée's I See a Voice is published by Flamingo.