in a slice which is a situation of
.
Thus a concurrent component lasts concurrently with the main object in any time-system.
[CHAPTER XV]
MATERIAL OBJECTS
[56. Material Objects]. 56.1 A material object is essentially a material object of a certain definite sort; namely, we define sorts of material objects, which are sets of objects with certain definite peculiarities, and a material object is such because it is a member of one of these sorts. For example a piece of wood is a material object because it belongs to the class of wooden objects and because this class possesses the requisite peculiarities. Similarly a charge of electricity is a material object for an analogous reason.
The objects which compose a set (
) form a sort of 'material' objects when (i) the objects of the set