Dave Speijer
First published:30 January 2020 https://doi.org/10.1002/bies.202000003
When do we know that a scientific theory is true? The instinctive answer, “when we have proven it,” while perfect for mathematics, is not up to the task in science because decades of confirmation can be swept away by one counter‐finding. This superficially simple observation functioned as one of the founding principles of the philosophy of science of Karl Popper. Thus, he proposed that we never know whether a scientific theory is “true”—a concept that would imply absolute certainty—but that we gain trust regarding its usefulness with each affirmation. The insight allowed him to distinguish between theories: those that could not be tested against experimental results (could not be “falsified”) he considered non‐scientific. Subsequent analysis of science showed that the reality of scientific research does not always bear out this strict rejection of theories upon finding contradictory evidence (who would have guessed?). One aspect that leads to problems in applying falsification is the strict separation of facts and theory that it assumes. In practice, the facts are seen through the prism of theory (the ruling “paradigm,” to use Thomas Kuhn's term), just as the theory is based on choices regarding what aspects of reality are relevant for its framework.
An entertaining illustration of the role of “facts” in deciding between alternative explanations, demonstrating the difference between “science theory” and “science practice,” can be found in “The Hunt for Vulcan.”1 The book is about the one planet in our solar system that you have never heard of: “Vulcan.” Newton's description of the mechanics of our solar system was almost perfect. However, the “almost” betrays a relatively small, but consistent, anomaly in the precession of the perihelion of Mercury, which many observers thought could be explained by an “extra” planet, Vulcan, near the sun. The book chronicles quite a few “facts” in the form of sightings! In reality, the anomalous precession makes sense when incorporating aspects predicted by Einstein's theory of general relativity. This example of a paradigm shift (going from Newtonian to relativistic physics) is often described as replacing “old” (incorrect) by “new” (correct) models, or even worse, as an illustration that all models are just social constructs (“just you wait for the next paradigm shift”). Instead, Newton's description is still very useful (“true”), but you need the overarching theory of relativity when, for example, (very) large masses or high speeds are involved. It goes without saying: scientific descriptions get better and more comprehensive over time.
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NOTA CÁUSTICA DESTE BLOGGER:
O autor afirmou que a teoria da evolução nos convida a tolerar exceções. Este blogger considera isso epistemologicamente errado. Razão? Uma teoria que previsse às exceções, às suas regras e generalizações não transmitiria conhecimento científico algum. Uma teoria que "tolera exceções", no entanto, terminará em um mapeamento 1:1 com o que se observa - nesse caso, a teoria não está funcionando, simplesmente vagando atrás dos dados como um filhote de cachorro na coleira.
Pano rápido, pois Popper não é bem-vindo nos arraiais darwinistas!
