Investigating necessity: essays on the role and status of metaphysical modality

Metaphysical necessity is one of contemporary philosophy’s widely-used tools for theorising. Since the 1970s, it has played central roles in metaphysics, epistemology, philosophy of language, philosophy of science, and beyond. Throughout philosophy, it is used to formulate important theories and hypotheses, and features pivotally in various influential arguments. Due to its wide use, metaphysical necessity has a multifarious theoretical role. To take a few examples, it is expected to be the broadest objective necessity, license paradigm essentialist claims, and obey liberal principles of recombination. Nevertheless, there has never been an attempt to investigate whether the many postulates of this role and applications of metaphysical necessity are compatible, in the sense that they can all be satisfied by a single notion of necessity. The aim of this thesis is to provide such an investigation. The Introduction outlines the themes of the thesis, and provides an overview of each individual essay. Essay One addresses certain foundational issues by criticising a popular form of scepticism towards metaphysical necessity. Essay Two investigates whether a family of natural principles of recombination can be integrated with the thesis that metaphysical necessity is the broadest objective necessity. Similarly, Essay Three studies whether paradigm portions of essentialist discourse can also be integrated with the same thesis. Essay Four draws on material from the previous essays to answer Timothy Williamson’s notorious expressive challenge to contingentist theories of modality. Finally, Essay Five provides a formal characterisation of so-called relative necessities which supports various claims and arguments made elsewhere in the thesis. Together, the essays constitute an investigation into the role and status of metaphysical necessity.