“The evidence speaks for itself,” or so many people say. That would contribute to an image of science as yielding unambiguous certainty. Once observations are made and the data collected, the conclusions unambiguously follow.
But should we accept this common belief, this Sacred Bovine, uncritically? For example, data are inert. They do not “speak.” People speak. In addition, people often disagree about the “facts,” even when they have observed the same thing. They conflict about how to interpret the evidence. Personal context matters. If science depends on something beyond just the evidence itself, then that exposes an important component of understanding for making any informed decision that relies on scientific claims.
Consider the case of Archibald Garrod and the discovery of inborn errors of metabolism (Gabel & Allchin, 2017). Garrod was a physician working in London in the 1890s. Imagine his surprise when he encountered a patient with red urine! What did that mean? Garrod had a background in chemistry, so he interpreted it as a chemical indicator. Could it help him decipher the nature of the patient's nervous disorder, known as chorea? He identified the pigment as hematoporphyrin. Ultimately, however, he found that it was not related to the disease.
But alert now to the color of urine, his attention was drawn to another patient a few years later whose urine was black. The condition, called alkaptonuria, was already documented—as early as 1822. The black color had been traced biochemically to the presence of homogentisic acid, which oxidizes in air or alkaline solutions and changes color. The compound's presence was apparently the result of a disruption in the breakdown of the familiar amino acid, tyrosine.
Alkaptonuria seemed not to harm the person's health. At the same time, no underlying cause was known. One researcher, during the early years …