a period of time. This is what I
mean by an 'event.' We discern some specific character of an event. But
in discerning an event we are also aware of its significance as a
relatum in the structure of events. This structure of events is the
complex of events as related by the two relations of extension and
cogredience. The most simple expression of the properties of this
structure are to be found in our spatial and temporal relations. A
discerned event is known as related in this structure to other events
whose specific characters are otherwise not disclosed in that immediate
awareness except so far as that they are relata within the structure.

The disclosure in sense-awareness of the structure of events classifies
events into those which are discerned in respect to some further
individual character and those which are not otherwise disclosed except
as elements of the structure. These signified events must include events
in the remote past as well as events in the future. We are aware of
these as the far off periods of unbounded time. But there is another
classification of events which is also inherent in sense-awareness.
These are the events which share the immediacy of the immediately
present discerned events. These are the events whose characters together
with those of the discerned events comprise all nature present for
discernment. They form the complete general fact which is all nature now
present as disclosed in that sense-awareness. It is in this second
classification of events that the differentiation of space from time
takes its origin. The germ of space is to be found in the mutual
relations of events within the immediate general fact which is all
nature now discernible, namely within the one event which is the
totality of present nature. The relations of other events to this
totality of nature form the texture of time.

The unity of this general present fact is expressed by the concept of
simultaneity. The general fact is the whole simultaneous occurrence of
nature which is now for sense-awareness. This general fact is what I
have called the discernible. But in future I will call it a 'duration,'
meaning thereby a certain whole of nature which is limited only by the
property of being a simultaneity. Further in obedience to the principle
of comprising within nature the whole terminus of sense-awareness,
simultaneity must not be conceived as an irrelevant mental concept
imposed upon nature. Our sense-awareness