The principle is best demonstrated by cases in which commitment to a false Why blocked recognition of a correct What. The following four examples are drawn from different centuries, different disciplines, and different institutional contexts. The pattern is uniform in every case.
4.1 Scurvy and the Acidity Theory
The What: In 1747, James Lind demonstrated through what is now recognized as the first controlled clinical trial that citrus fruit cured scurvy. By 1799, the Royal Navy required daily lemon juice for sailors. Scurvy virtually disappeared from British ships.
The false Why: No one knew why citrus worked (vitamin C would not be identified until the 1920s). The prevailing theory attributed the cure to the acidity of the fruit. Since lemons and limes are obviously acidic, the explanation seemed self-evident.
The contamination: In 1860, the Navy switched from Mediterranean lemons to West Indian limes, partly for colonial trade convenience. Since limes are more acidic than lemons, the acidity theory predicted they would be even more effective. In fact, limes contain only a quarter of the vitamin C of lemons. Worse, the lime juice was stored in copper containers and processed in ways that further destroyed the vitamin C. Scurvy returned on long voyages. But the acidity theory prevented recognition of the problem: the substitute was more acidic, so by the prevailing Why, it should have been superior. The What (citrus cures scurvy) was still correct, but the false Why (because acid) had led the Navy to substitute an ineffective remedy for an effective one.
The cost: By the time of Scott’s 1911 Antarctic expedition, the cure for scurvy had been effectively forgotten. A Royal Navy surgeon on the expedition said: “There was little scurvy in Nelson’s days; but the reason is not clear.” The reason was perfectly clear a century earlier. The false Why had erased the correct What.....
