son. The
recognised objects of one event are compared with the recognised objects
of another event. The comparison may be between two events in the
present, or it may be between two events of which one is posited by
memory-awareness and the other by immediate sense-awareness. But it is
not the events which are compared. For each event is essentially unique
and incomparable. What are compared are the objects and relations of
objects situated in events. The event considered as a relation between
objects has lost its passage and in this aspect is itself an object.
This object is not the event but only an intellectual abstraction. The
same object can be situated in many events; and in this sense even the
whole event, viewed as an object, can recur, though not the very event
itself with its passage and its relations to other events.

Objects which are not posited by sense-awareness may be known to the
intellect. For example, relations between objects and relations between
relations may be factors in nature not disclosed in sense-awareness but
known by logical inference as necessarily in being. Thus objects for our
knowledge may be merely logical abstractions. For example, a complete
event is never disclosed in sense-awareness, and thus the object which
is the sum total of objects situated in an event as thus inter-related
is a mere abstract concept. Again a right-angle is a perceived object
which can be situated in many events; but, though rectangularity is
posited by sense-awareness, the majority of geometrical relations are
not so posited. Also rectangularity is in fact often not perceived when
it can be proved to have been there for perception. Thus an object is
often known merely as an abstract relation not directly posited in
sense-awareness although it is there in nature.

The identity of quality between congruent segments is generally of this
character. In certain special cases this identity of quality can be
directly perceived. But in general it is inferred by a process of
measurement depending on our direct sense-awareness of selected cases
and a logical inference from the transitive character of congruence.

Congruence depends on motion, and thereby is generated the connexion
between spatial congruence and temporal congruence. Motion along a
straight line has a symmetry round that line. This symmetry is expressed
by the symmetrical geometrical relations of the line to the family of
planes normal to it.

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