Every actual occasion involves every other, and to know any one is to know the whole universe. Actual occasions are spatio-temporal aspects of process, a nexus of which we call an object. An object is nothing but a continuous process of actual occasions as we experience them in their externalised condition. There is no fixed object anywhere. An event is a series of actual occasions revealed in perception as demonstrated in a molecule for a few moments.
Objects are more complex formulations of such events.
The objectness of an object is in its capacity to be experienced in perception. Every actual occasion is sensitive to the existence of others, and thus to the entire universe. All actual occasions take account of each other, and in some way, subtler than even sense-perception, 'perceive' each other. There is a kind of pervasive 'feeling' of every actual occasion for the others in the universe. Whitehead uses the word 'feeling' in quite a different sense from the one in which we are used to understand it, and makes it more fundamental than the conscious level of the mind in waking life.