When is a Concept a True Concept?

This chapter examines the criteria that a concept must satisfy to be regarded as a true concept. An important requirement is that a concept should have all the properties that are expected of it. The semiconductor hole is taken as a case study to determine whether it is a true particle. It is found that it does not have an identifiable antiparticle and is thus classified as a quasiparticle. This example is used to divide concepts into quasi-concepts and true concepts. The important role of the concept of quasiparticles in physics is noted.