Behavioural scientists show altruism to exist as a distinctive personality. Yet when subjected to philosophical scrutiny, and altruistic personality is prima facie paradoxical. To motivate herself to help others, the altruist needs ‘extensivity’, the capacity to compassionately identify with others. To aid others effectively, however, the altruist must have individuation, the possession of highly developed autonomy and self-efficacy. We assert that a better understanding of the relationship between concern for others and concern for self reveals the paradox to be merely apparent. We find that, in extending themselves in caring behaviours, altruists actually enhance their individuality. Moreover, given the differences between compassion and empathy and the way empathy medicates between compassionate co-feeling and individuation, extensivity and individuation do not necessarily conflict. We conclude therefore that despite appearances the altruistic personality is a coherent construct.