 According to Shepherd’s definition, causality is a compositional determination relation. The pre-existing entities which combine to form a cause are variously called “objects”, “natures”, “masses of qualities”, and “unknown circumstances in nature”, among other things. By “objects”, Shepherd means things in natural kinds, e.g., a fire, a log, and bread. In general, an object is a “mass of qualities” which is or may be perceived by sense (ERCE: 64). The object is “nothing distinct from its qualities” (ERCE: 161–2). “[I]n this union, Cause and Effect, are synchronous, and they are but different words for the same Essence” (ERCE:  57).[5]  Regarded in this way, a quality belongs to an object as a part belongs to a whole, not that in which a predicate belongs to a subject. But although cause and effect are one essence, there is some difference between them: one is really productive of the other. The cause determines the qualities included in the mass. In effect, the ideas of cause and effect are two ways of representing the same thing which are not entirely without basis in the thing. With regard to the term “nature, it is sometimes used to stand for the unknown causes of the sensory appearances which come to exist when objects are perceived by sense. 