A significant body of research and analysis concerning wellbeing has emerged across a number of social research disciplines, yet the concept of wellbeing does not admit of any unified meaning. Philosophical accounts of wellbeing are traditionally divided into three categories: hedonistic, desire-satisfaction and objective list theories, reflecting longstanding doctrinal divisions in normative ethics. Rejecting the foundational monism associated with these approaches, Amartya Sen has proposed a pluralist 'capabilities' approach to personal wellbeing based on freedom of choice and the Aristotelian notion of a 'function'. Recent Australian wellbeing research also shows promising signs of moving beyond reductive income-based metrics towards plural indicators of poverty and social disadvantage. This paper reprises Aristotle's distinctive account of perfect wellbeing (eudaimonia) in the Nicomachean Ethics and investigates Sen's approach in its light, suggesting that future Australian research in the spirit of Sen's pluralism may benefit from Aristotelian insights into the 'thickness' of freedom implicated in personal wellbeing.