Health and functional efficiency.

This essay argues that what is central to Christopher Boorse's biostatistical theory of disease as statistically subnormal part function (BST) are comparisons of the "functional efficiency" of parts and processes and that statistical considerations serve only to pick out a healthy level of functional efficiency. On this interpretation, the distinction between health and pathology is less important than comparisons of functional efficiency, which are entirely independent of statistical considerations. The clarifications or revisions of the BST that this essay offers are friendly amendments that render moot some of the most prominent criticisms of Boorse's account.