Epistemological angle: The example the surrogate literature is built on, given its own entry here because the structure deserves examination rather than citation. Every element of the reasoning was sound in isolation. Ectopy predicts sudden death — true, and well established. These drugs suppress ectopy — true, and confirmed in every patient before randomisation. Therefore suppressing ectopy should prevent death — false, and false in a way no amount of further observational data would have exposed. The error is the assumption that a marker on the causal pathway is a lever on it: ectopy was a symptom of a diseased myocardium, and the drugs suppressed the symptom while making the myocardium worse. This is the surrogate fallacy at maximum strength, with the additional detail that the trial design itself enrolled only responders, which should have made the result more favourable and did not.

Epistemological angle: The clearest demonstration available that evidence underdetermines practice. Neither body was incompetent, neither had different data, and their advice to surgeons was opposite. The entire disagreement reduces to whether one reference class — asymptomatic venographic clot — licenses inference to another, fatal embolism. That is a question about surrogate validity, not about the trials, and no additional trial of the same design could have settled it.

Epistemological angle: A threshold calibrated to what a procedure can achieve cannot then be used as evidence that it achieves anything. The criterion is not literally unfailable — eight of the thirty-four shoulders did fail it, so the study could have come out worse than it did. What it lacks is any anchor outside the tradition being assessed: nothing but that tradition determines where the bar sits, so a poor result and a good one are both measured against a standard the operation's own advocates set. And the pattern is not isolated: Williams and Rockwood reported 86% satisfactory by this standard in 1996, Sanchez-Sotelo and Cofield 67% in 2001. Three decades of apparently comparable evidence, all resting on a benchmark with no external referent.

Epistemological angle: "Clinically meaningful improvement" turns out to be a property of the instrument rather than of the patient. The same person, at the same visit, is a success on one validated measure and a failure on another. Which means the choice of primary outcome in any trial is a covert decision about who will count as helped — a decision made before any data are collected, usually without discussion, and capable of determining the result.

Epistemological angle: Included here rather than among the trials because of what preceded it. Surgical volume for these fractures had been climbing for a decade on the strength of anatomical reasoning — restore the anatomy and function follows — without a trial supporting it. Mechanistic plausibility functioned as sufficient warrant to adopt, and only a large pragmatic trial was accepted as sufficient warrant to reconsider. The two standards are not the same size.