PART 1
INTRODUCTORY MATERIAL
essential feature of the notion of substantiality or being. 7 §4; 2. 11 §3), 'truly single beings' (T2. Now though nothing could be clearer than that for Leibniz substantiality means unity (of a per se and non-accidental kind), it is nothing like so dear exactly what he counts as examples of such unities. The first of these is a theory about substances as material substances; the second is a theory about substances as immaterial substances.