This is one instance of the indeterminateness of sense-awareness.

Exactness is an ideal of thought, and is only realised in experience by the selection of a route of approximation.
The absence of maximum and minimum durations does not exhaust the properties of nature which make up its continuity.

The passage of nature involves the existence of a family of durations.

When two durations belong to the same family either one contains the other, or they overlap each other in a subordinate duration without either containing the other; or they are completely separate.

The excluded case is that of durations overlapping in finite events but not containing a third duration as a common part.
It is evident that the relation of extension is transitive; namely as applied to durations, if duration A is part of duration B, and duration B is part of duration C, then A is part of C.Thus the first two cases may be combined into one and we can say that two durations which belong to the same family _either_ are such that there are durations which are parts of both _or_ are completely separate.
Furthermore the converse of this proposition holds; namely, if two durations have other durations which are parts of both _or_ if the two durations are completely separate, then they belong to the same family.
The further characteristics of the continuity of nature--so far as durations are concerned--which has not yet been formulated arises in connexion with a family of durations.