Harbour's empirical thesis - that the primary object of study for persons are partitions, not syncretisms - transforms a sea of data into a categorical problem of the attested and the absent. Positing, innovatively, that features denote actions, not predicates, he shows that two features alone generate all and only the attested systems. This apparently poor inventory yields rich explanatory dividends, covering the morphological composition of person, its interaction with number, its connection to space, and properties of its semantics and linearization.