Passage
Expert standing is usually explained by the record: practitioners earn deference by being visibly right, their verdicts tested against outcomes. Graders who sort a fibre crop are the model case. A grader’s verdict is checked within weeks by the buyer, and one who is often wrong soon has no custom. Where such a loop runs, the explanation is hard to improve on.
The explanation is only as good as the loop, and many fields have none. A practitioner certifying how long a machine will last issues a judgment legible only after decades, by which time so much has intervened that the advice can be reconciled with almost any outcome. Deference there cannot rest on a demonstrated record, since no record is available to point to. What stands in its place is conformity to a procedure the practitioners have themselves codified: the client credits the method, and the practitioner for following it.
Some observers locate standing instead in control of entry: an occupation that can decide who may practise, they argue, commands deference whatever the quality of its judgments, the codified procedure mattering only as examinable content that makes exclusion look principled. The argument has force, and its sequence is often the actual one. But it predicts too much. Occupations that hold the gate with equal firmness differ widely in the deference they are shown, and some have seen that deference fall away while their control over entry remained intact. Closure may well be necessary to the standing these fields enjoy; it is plainly not sufficient to maintain it.
What the closure account passes over is who may pronounce a judgment mistaken. Where outcomes are legible, error is declared by the world. Where they are not, an error exists only when a body of peers agrees to call it one, and the procedure that licensed the verdict also supplies the standard by which it is reviewed, so a review may find the method properly applied and the result merely unlucky. Deference therefore survives error. Some such arrangement is unavoidable where the world declines to answer promptly, but it changes the question worth asking: not how an occupation came by its authority, but who, apart from its own members, is placed to say whether the authority is deserved.
