Periculum Cur 04

Four historic examples of periculum cur

4. Four Cases of Periculum Cur

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.

4.2 Peptic Ulcers and the Stress/Acid Theory

The What: In 1983, Barry Marshall and Robin Warren identified Helicobacter pylori as the bacterial cause of most peptic ulcers. Marshall famously drank a culture of the bacterium to prove it caused gastritis.

The false Why: For decades, the medical establishment had attributed ulcers to stress, spicy food, lifestyle choices, and excess stomach acid. The Why was deeply entrenched: ulcers were a “stress disease,” and a massive pharmaceutical industry had been built around acid-suppression drugs that managed symptoms without curing the underlying cause.

The contamination: The false Why actively blocked the correct What for decades. A 1954 study failed to find bacteria in stomach biopsies, which effectively established the acid theory as dogma. Marshall and Warren faced ridicule, rejection, and institutional resistance. Their abstract was rejected from the Gastroenterology Society of Australia meeting (one of only 12 rejected out of 68 submitted). Their Lancet paper faced extensive delays. The reason was not that the evidence was weak. The reason was that the evidence contradicted the accepted Why, and the accepted Why was load-bearing for a therapeutic paradigm, a pharmaceutical industry, and thousands of medical careers built around acid suppression. As late as the mid-1990s, most U.S. physicians were still not treating ulcers with antibiotics.

The cost: Decades of chronic suffering and recurring ulcers for millions of patients who could have been cured with a short course of antibiotics. Marshall and Warren received the Nobel Prize in 2005, more than twenty years after their discovery. The correct What (bacteria cause ulcers) was available throughout. The false Why (stress and acid cause ulcers) prevented it from being accepted.

4.3 Phlogiston and the Nature of Combustion

The What: Metals gain weight when they burn. This had been observed repeatedly by careful experimenters throughout the seventeenth and eighteenth centuries. The observation was robust, replicable, and unmistakable.

The false Why: The phlogiston theory held that combustion involved the release of a substance called phlogiston from the burning material. This theory predicted that burning should result in weight loss, not weight gain, since the material was supposedly losing its phlogiston content.

The contamination: Faced with the clear empirical What (metals get heavier when they burn), defenders of phlogiston did not abandon the Why. They modified it. Some proposed that phlogiston had negative weight. Others suggested that phlogiston was released while something else from the air was simultaneously absorbed, and the net effect happened to be positive. The false Why was adjusted to accommodate the What rather than surrendering to it. The result was a century of baroque theorizing in which the simple, observable fact of how combustion involves absorption from the air was buried under increasingly desperate rescue operations for a fictional substance. Lavoisier’s oxygen theory eventually prevailed, but the transition took decades longer than it should have because the phlogiston Why provided a framework that could be endlessly modified to accommodate contradictory evidence.

The cost: Historians of chemistry have argued that the commitment to phlogiston delayed the development of energy concepts and the understanding of electricity in chemistry by decades. The phlogiston theory was already conceptually linked to ideas about energy transfer that, had they been pursued without the false explanatory framework, could have led to earlier recognition of the role of electrons in chemical reactions.

4.4 Neo-Darwinian Evolution and the Modern Synthesis

The What: The complete telomere-to-telomere ape genome assemblies of Yoo et al. (2025) document approximately 410 million base-pair differences between humans and chimpanzees, of which approximately 205 million fall on the human lineage. The human-derived fixation rate, calculated from observed historical data, is one fixation per approximately 27,600 effective generations.

The false Why: The Modern Synthesis holds that random mutation and natural selection, operating over deep time, are sufficient to produce the observed genetic divergence. This Why has been treated as established fact for over a century.

The contamination: When the mathematics of fixation rates are actually calculated, the mechanism does not merely fall short. Applied to the human lineage, the human-derived rate of one fixation per 27,600 effective generations yields a maximum of 8 fixations in the available time. The requirement is 205 million. This is not a marginal shortfall. It is not a matter of adjusting parameters. It is a gap of more than seven orders of magnitude, a fundamental mismatch between mechanism and observation. Yet this mathematical impossibility has been known in outline since the 1966 Wistar Institute symposium, where mathematicians and physicists presented calculations showing that the available time was insufficient. The biologists present dismissed the concerns. They could afford to dismiss them because the Why of natural selection acting on random mutation was so deeply entrenched that no amount of mathematical contradiction could dislodge it. The Why was used to erase the What: “The numbers must work out somehow, because we know the mechanism is correct.”

The cost: Sixty years of research wasted on a foundation known to be mathematically false the entire time. Every paper in evolutionary biology that assumes the neo-Darwinian mechanism can do the work claimed of it is constructing explanations using a mechanism that is mathematically incapable of producing the phenomena it purports to explain. The question of how complex life arose from simpler forms is entirely open, but the false Why prevents the real reason from ever being considered, because asking it requires first admitting that the accepted answer is wrong.