Moral enhancement and behavioral trait variance

Proponents of moral enhancement often link certain traits to virtuous behavior but typically focus on average trait scores, neglecting individual behavioral trait variance. Behavioral trait variance refers to the range of behaviors a person exhibits within a trait, which may partly arise from genetic factors independent of mean scores. Using Martha Nussbaum's capabilities approach and virtue ethics, I argue that increasing behavioral trait variance could promote moral flourishing. For example, a consistently disagreeable teacher might excel in specific contexts, like a philosophy seminar. However, such a teacher will struggle to find Aristotle's moral meaning of friendliness, limiting their virtue across diverse contexts. Since social virtues are context-dependent, reducing behavioral trait variance through personality enhancement could also hinder an individual's ability to achieve virtues or capabilities. This article investigates behavioral trait variance's moral role within virtue ethics and calls for other moral enhancement theories to address the ethical significance of behavioral trait variance and its potential impact on moral flourishing.