Thus _A_, conceived merely in respect to its relationships to other eternal objects, is ‘_A_ conceived as _not-being_’; where ‘not-being’ means ‘abstracted from the determinate fact of inclusions in, and exclusions from, actual events.’ Also ‘_A_ as _not-being_ in respect to a definite occasion α’ means that _A_ in all its determinate relationships is excluded from α. Again ‘_A_ as _being_ in respect to α’ means that _A_ in some of its determinate relationships is included in α. But there can be no occasion which includes _A_ in all its determinate relationships; for some of these relationships are contraries. Thus, in regard to excluded relationships, _A_ will be _not-being_ in α, even when in regard to other relationships _A_ will be _being_ in α. In this sense, every occasion is a synthesis of _being_ and _not-being_. Furthermore, though some eternal objects are synthesised in an occasion α merely _quâ not-being_, each eternal object which is synthesised _quâ being_ is also synthesised _quâ not-being_. ‘_Being_’ here means ‘individually effective in the aesthetic synthesis.’ Also the ‘aesthetic synthesis’ is the ‘experient synthesis’ viewed as self-creative, under the limitations laid upon it by its internal relatedness to all other actual occasions. We thus conclude—what has already been stated above—that the general fact of the synthetic prehension of all eternal objects into every occasion wears the double aspect of the indeterminate relatedness of each eternal object to occasions generally, and of its determinate relatedness to each particular occasion. This statement summarises the account of how external relations are possible. But the account depends upon disengaging the spatio-temporal continuum from its mere implication in actual occasions—according to the usual explanation—and upon exhibiting it in its origin from the general nature of abstract possibility, as limited by the general character of the actual course of events. The difficulty which arises in respect to internal relations is to explain how any particular truth is possible. In so far as there are internal relations, everything must depend upon everything else. But if this be the case, we cannot know about anything till we equally know everything else. Apparently, therefore, we are under the necessity of saying everything at once. This supposed necessity is palpably untrue. Accordingly it is incumbent on us to explain how there can be internal relations, seeing that we admit finite truths. Since actual occasions are selections from the realm of possibilities, the ultimate explanation of how actual occasions have the general character which they do have, must lie in an analysis of the general character of the realm of possibility.