e accustomed to associate an event with a certain melodramatic
quality. If a man is run over, that is an event comprised within certain
spatio-temporal limits. We are not accustomed to consider the endurance
of the Great Pyramid throughout any definite day as an event. But the
natural fact which is the Great Pyramid throughout a day, meaning
thereby all nature within it, is an event of the same character as the
man's accident, meaning thereby all nature with spatio-temporal
limitations so as to include the man and the motor during the period
when they were in contact.

We are accustomed to analyse these events into three factors, time,
space, and material. In fact, we at once apply to them the concepts of
the materialistic theory of nature. I do not deny the utility of this
analysis for the purpose of expressing important laws of nature. What I
am denying is that anyone of these factors is posited for us in
sense-awareness in concrete independence. We perceive one unit factor in
nature; and this factor is that something is going on then--there. For
example, we perceive the going-on of the Great Pyramid in its relations
to the goings-on of the surrounding Egyptian events. We are so trained,
both by language and by formal teaching and by the resulting
convenience, to express our thoughts in terms of this materialistic
analysis that intellectually we tend to ignore the true unity of the
factor really exhibited in sense-awareness. It is this unit factor,
retaining in itself the passage of nature, which is the primary concrete
element discriminated in nature. These primary factors are what I mean
by events.

Events are the field of a two-termed relation, namely the relation of
extension which was considered in the last lecture. Events are the
things related by the relation of extension. If an event A extends
over an event B, then B is 'part of' A, and A is a 'whole' of
which B is a part. Whole and part are invariably used in these
lectures in this definite sense. It follows that in reference to this
relation any two events A and B may have any one of four relations
to each other, namely (i) A may extend over B, or (ii) B may
extend over A, or (iii) A and B may both extend over some third
event C, but neither over the other, or (iv) A and B may be
entirely separate. These alternatives can obviously be illustrated by
Euler's diagrams as they appear in logical textbooks.

The continuity of nature is the continuity of events.