Abstract

In this chapter we show how pharmacological researchers manage uncertainty when using high-throughput screening (HTS) techniques. HTS allows researchers to rapidly survey the activities of large numbers of chemical compounds against a biological target. However, not all molecules that show promising biological activity during screening will be suitable for clinical use. Researchers use the concept of druglikeness to manage this uncertainty about whether a biologically active molecule will be suitable for pharmacological use. We introduce our approach in Sect. 7.1, during which we argue that the methodological choices we discuss are predicated on epistemic assumptions. We then give a brief overview of drug discovery in Sect. 7.2, and introduce HTS in more detail in Sect. 7.3. Section 7.4 then introduces druglikeness as an epistemic strategy for managing uncertainty, before discussing one of the heuristic tools, known as the rule of five, that is used by pharmacologists to reduce uncertainty about druglikeness. We conclude this chapter in more philosophical territory by considering druglikeness as a kind of extrapolation. Here, we argue that druglikeness does not seem to invoke biological mechanisms, but instead exploits the chemical capacities of molecules. The aim of this exploration is to provide a normative account of the role(s) played by values and philosophical assumptions in employing different epistemic and methodological strategies in scientific practice.