Abstract

What is liberty, and can it be measured? In this paper I argue that the only way to have a liberty metric is to adopt an account of liberty with specific and controversial features. In particular, I argue that we can make sense of the idea of a quantity of liberty only if we are willing to count certain purely agential constraints, such as ignorance and physical incompetence, as obstacles to liberty in general. This spells trouble for traditional ‘negative’ accounts, against which I argue directly. My aim is to establish the following somewhat surprising claim: that if a political theory is to contain a principle regarding the protection, maximisation, or equalisation of some liberty, it must concern itself--on pain of conceptual incoherence--with the positive preconditions (in addition to the negative preconditions) of that liberty’s effective exercise.