Jonathan Livingstone-Banks

Nosology is the science of defining and classifying diseases. Meta‐nosology is the study of how we do this, on what principles nosological practices are based, the quality of the resulting medical taxonomy, and primarily whether/how diseases can be defined better than they are now. In modern Western medicine, there are a wide variety of ways in which diseases are defined and categorized. Examples include by the symptoms they present with (syndromic), their underlying causes (etiological), the biological mechanisms involved (pathogenetic), available treatments, historical precedent, and through diagnostic exclusion. Here, I explore the hypothesis that how we define diseases has an impact on how (and how effectively) we research and treat them. I explore the philosophical implications of this thesis and suggest a direction that the underlying metaphysics of disease definition might follow. I conclude that further research is warranted into whether our current disease definitions could be improved upon.

Conventionalism about essence is the view that truths about what is (and isn’t) essential to things are based upon talk and thought about the world, rather than mind-independent facts. This chapter presents motivations for conventionalism, and explains how conventionalism can be (and has been) developed to accommodate essences that can only be discovered with the help of empirical investigation, like “water is H2O” or “Obama is human”. We examine a range of objections that have been raised against conventionalism—often presented dismissively and decisively—and show how conventionalism has ample resources with which to plausibly respond to these challenges.

This project is an investigation into the prospects for an antirealist theory of essence. Essentialism is the claim that at least some things have some of their properties essentially. Essentialist discourse includes claims such as “Socrates is essentially human”, and “Socrates is accidentally bearded”. Historically, there are two ways of interpreting essentialist discourse. I call these positions ‘modal essentialism’ and ‘neo-Aristotelian essentialism’. According to modal essentialism, for Socrates to be essentially human is for it to be necessary that he be a human if he exists, and for Socrates to accidentally have a beard is for it to be contingent that Socrates has a beard if he exists. According to neo-Aristotelian essentialism, objects have definitions in something like the way words do. For Socrates to be essentially human but accidentally bearded is for it to be part of the definition of Socrates that he is human, but not part of that definition that he is bearded. I argue that both are susceptible to antirealist interpretation. This thesis sets about showing that this is the case. In Chapters One and Two I investigate neo-conventionalist theories of modality, in the hope of using such a position to develop an antirealist modal essentialism. In Chapter Three I discuss the debate between modal and neo-Aristotelian essentialism and conclude that it is by no means settled. In Chapter Four I develop an antirealist neo-Aristotelian essentialism based on the mechanism of one of the neo-conventionalist accounts of modality. In Chapter Five I argue that this account is in a better position to give an essentialist theory of necessity than its realist counterparts. I conclude that, regardless of whether one is a modal or neo-Aristotelian essentialist, antirealist essentialism is a viable theory of essence that is worthy of consideration in contemporary debate.

Traditional conventionalism about modality claims that a proposition is necessarily true iff it is true by convention. In the wake of the widespread repudiation of truth-byconvention, traditional conventionalism has fallen out of favour. However, a family of theories of modality have arisen that, whilst abandoning truth-by-convention, retain the spirit of traditional conventionalism. These ‘neo-conventionalist’ theories surpass their forebears and don’t fall victim to the criticisms inherited through truth-by-convention. However, not all criticisms levelled at traditional conventionalism target truth-by-convention. Any conventional theory of modality must face the contingency problem. This claims that the contingency of our linguistic conventions jeopardises the necessity of the necessities they determine. I present the contingency problem as relevant to both the traditional conventionalist and the neo-conventionalist. I examine a response from Einheuser that builds upon a response from Wright. I show that the Einheuser response does more to accommodate the conventionalist’s modal beliefs, but that it does not fully satisfy some further conditions that ought to be laid upon such a response. I then suggest how the response can be revised so as to satisfy these conditions. The resulting model of conventionalism is compatible with the validity of S4, and suitably in the spirit of conventionalism.