This chapter generalizes the ideas given in the previous chapter. It sets out the notion of a model based on a set of theories. One of these theories is the logic itself. It is, so to speak, the correct theory of theories. It correctly states the principles under which all the theories (including itself) are closed. But each theory has associated with it a closure operator. Some of these operators get the principles of theory closure quite wrong in the sense that they do not apply correctly to every theory in the model. The interaction between these closure operators can be altered in various ways, giving rise to different logical systems. The resulting formal semantics can be represented in the manner of Kit Fine’s “Models for Entailment”.

This chapter discusses whether the appropriation of Kuhnian thoughts by the so-called Strong Programme in the sociology of scientific knowledge is appropriate. In order to answer the question of appropriate appropriation, Kuhn’s and the Strong Programme’s stances on two “isms” are compared: relativism and naturalism. It is shown that the Strong Programme clearly goes beyond Kuhn and breaks more radically with philosophical tradition. Nevertheless, there are also philosophical continuities and similarities.