I argue for a conception of health as a person's ability to achieve or exercise a cluster of basic human activities. These basic activities are in turn specified through free-standing ethical reasoning about what constitutes a minimal conception of a human life with equal human dignity in the modern world. I arrive at this conception of health by closely following and modifying Lennart Nordenfelt's theory of health which presents health as the ability to achieve vital goals. Despite its strengths I transform Nordenfelt's argument in order to overcome three significant drawbacks. Nordenfelt makes vital goals relative to each community or context and significantly reflective of personal preferences. By doing so, Nordenfelt's conception of health faces problems with both socially relative concepts of health and subjectively defined wellbeing. Moreover, Nordenfelt does not ever explicitly specify a set of vital goals. The theory of health advanced here replaces Nordenfelt's (seemingly) empty set of preferences and society-relative vital goals with a human species-wide conception of basic vital goals, or 'central human capabilities and functionings'. These central human capabilities come out of the capabilities approach (CA) now familiar in political philosophy and economics, and particularly reflect the work of Martha Nussbaum. As a result, the health of an individual should be understood as the ability to achieve a basic cluster of beings and doings-or having the overarching capability, a meta-capability, to achieve a set of central or vital inter-related capabilities and functionings.