Abstract
The principal thesis of A Study of Concepts is that a concept is individuated by its possession condition. Concepts are here understood to be sliced as finely as epistemic possibility. So now and 6 o’clock are different concepts, even if, in context, they pick out the same time; likewise for the observational concept circular and the complex concept locus of coplanar points equidistant from a given point. In the simplest cases, a possession condition is stated by giving a true, individuating statement of the form.
