AAP 2025 CONFERENCE

What role should empirical methods play in political philosophy? What might be the merits of employing social science methods to address the fundamental questions political philosophers explore, such as what makes the state politically legitimate or what is the nature of a good society? A useful point of comparison here is political science. Although political science and political philosophy are closely adjacent disciplines, political scientists typically make far greater use of empirical methods. Moreover, many political scientists are highly critical of what they see as the unacceptable aprioristic methods employed by great deal of contemporary political philosophy. Such criticisms are, however, highly contentious and contested. Many political philosophers are opposed, on primarily normative political grounds, to such moves that they regard as embodying the methodological vice of “scientism”. What should we think? Might there be specifically political reasons for rejecting some methodological practices? Might there also be straightforward philosophical grounds for objecting to strong empiricist programs of reform? In this talk, I shall begin by considering the disagreement between the Vienna Circle and the Frankfurt School on whether philosophy should model itself on the natural sciences before providing a defence of the thought that when investigating the normative questions that lie at the heart of political philosophy, non-empirical philosophical speculation has a significant role to play. In the final section, I shall briefly outline some reasons why this methodological stance matters politically.

Thinking in terms of probabilities can give us a valuable lens on uses of vague language. In particular, it holds out the promise of bringing formally-tractable theories closer to empirical observations about how speakers actually use vague language. However, most existing applications of probability to vague language assume a classical approach to probability. This may be fine as a first approximation, but does not deal well with certain observed phenomena that have been used to motivate formal treatments of vague language based on nonclassical logics. Here I have in mind some phenomena around what have been called "borderline contradictions". In particular, speakers seem relatively happy to agree, of a borderline case of "tall" (for example), that they are both tall and not tall; but speakers are also resistant, in such cases, to agree that such a person is tall, or that they are not tall. These phenomena have been used to motivate three-valued non-probabilistic theories of vague language.
In this talk, try to bring these approaches together, in a way that hopefully achieves some of the virtues of both probabilistic and nonclassical approaches. I give an outline of some of the reasons probabilistic approaches to vague language seem promising and enlightening. Then I turn to borderline contradictions, arguing that classical probabilities are not well-suited for understanding this phenomenon. Finally, I make steps towards a theory of nonclassical probabilities that (I hope) can achieve the goods of existing probabilistic theories of vagueness, while fitting with a plausible approach to borderline contradictions.