From the article:

Suppose that apples sell for more than oranges and Parliament in [its] wisdom decides that, at last, apples and oranges must be compared. Not by shoppers — shoppers are biased, they merely reveal what they are willing to pay — but by a tribunal, which will determine whether apples and oranges are of truly equal value and thus must sell at the same price.

What would the tribunal need to know?

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To determine the “just” price of apples and oranges, the tribunal would need the entire general-equilibrium system.

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Britain is now running this experiment in the labor market–Is a retail worker equal to a warehouse worker? A canteen worker equal to a coal miner? A dinner lady equal to a gravedigger?

Under the Equality Act’s “equal value” provisions, tribunals compare jobs by scoring their intrinsic properties — effort, skill, responsibility, working conditions — the labor theory of value applied to labor. How is it going? The Tesco litigation began in 2018; the tribunal’s fact-finding hearing ran 36 days, its judgments run to more than 900 pages resting on some 19,000 pages of training manuals, and the independent experts have yet to begin the report that will actually say whether a shelf-stacker’s job equals a warehouse worker’s. Eight years, and the calculation has not started. Apples and oranges, adjudicated but not, as Orwell or Marx or Stafford Beer might have imagined, by a industrial bureaucracy or by an all-knowing artificial intelligence but by lawyers and commissions and tribunals. The worst of all worlds.

And having discovered that the tribunal cannot price two jobs in a decade, the government now proposes to add race and disability comparisons and an enforcement unit to publish official guidance on which reasons for a wage difference are permissible. A bureau of allowable scarcities.

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The market compares apples and oranges every day. It is the only institution that can. But there is a deeper error here than computation. Suppose the tribunal succeeded. Suppose that after another decade it delivered the true and final score, shelf-stacker versus warehouseman. What would it have found? Not justice. A wage is not a grade on your character or a measure of your worth as a human being. A wage is a price — a report on how scarce your skills are relative to the desires of people you will never meet. Nurses are not morally less worthy than plumbers should they earn less than plumbers or vice-versa, and no one thinks otherwise except the tribunals.