Barbara Thayer-Bacon (1999) objects to the minimum proficiency examinations that are mandated for school students in Ohio. Similar tests are required by, or are under consideration by, governments in many other parts of the world. Various writers have objected to one or other of these tests by arguing that they are crude, invalid, unreliable, unprofessional, inefficient, overpriced, irrelevant, limiting, anti-educational, outdated, or just silly. On the contrary, Thayer-Bacon disclaims any expertise in testing. She regards the tests as "a wonderful example of what happens when people assume knowledge is separate from knowers, when they try to separate ideas, as objects, from people, as subjects". If Thayer-Bacon is right then this is a serious matter. There is a dangerous delusion that has been embedded in the philosophical tradition almost from its inception, which is affecting the ordinances of regional governments and the practices in classrooms, and which one must avoid. It is important to establish exactly what this delusion is. Thayer-Bacon provides various clues, but none is sufficient to enable an individual to identify the delusion. In this article, the author talks about Barbara Thayer-Bacon and her notion of knowers and the known. (Contains 37 notes.)