Four prejudices about scientific discovery and how to resolve them – with Alzheimer´s disease as a case study

In this paper, I argue that four common prejudices have proven to be rather persistent obstacles to the development of an appropriate philosophical understanding of scientific discoveries: (1) the, already somewhat out-dated prejudice according to which scientific discoveries are non-rational and therefore not apt to philosophical analysis, (2) the prejudice that newly discovered scientific entities always possess sharp conceptual boundaries, (3) the prejudice that the notion of scientific discovery entails a commitment to realism about discovered entities, and (4) the prejudice that scientific discoveries are point events. In Sects. 2 to 5, I will present evidence against these four prejudices, mainly relying on the discovery of Alzheimer´s disease. In particular, while Kuhn (The Essential Tension, Chicago: The University of Chicago Press, 165–177, 1962) had dismissed prejudice (4) only with regard to discoveries that violate an existing paradigm, I will show it to be untenable even in a case (Alzheimer´s disease) where no paradigm has already prevailed. The rejection of prejudices (1) to (4) will lead us to a new picture according to which scientific discoveries do not always present fixed and conceptually well-determined entities, but may rather be constituted by successive steps of knowledge acquisition with respect to some moving target (Sect. 6).