Whitehead has some of the most conceptually liberating notions for thinking about time, space, and extensionality, but unfortunately, they can be difficult to grasp. Whitehead places space and time, as well as any other possible dimension, on what he terms the extensive continuum. This is the widest possible field which we are able to imagine. The bare extensive continuum is merely a field of potential that can be filled by actual entities through extensive connection.
Any kind of extension, either through space or time, takes place on the extensive continuum. Any kind of dimensionality is a form of extension, and the forms of extension which we bear witness to are not the only ways in which actual entities can and do manifest themselves. The three spatial dimensions which we are used to could be different. It’s entirely possible for there to be a society of entities which live in a “flatland” for instance. This notion of time as one type of extensive connectedness allows for thinking about becoming and process outside of notions of pure time.
What is meant by extensive connectedness deserves some clarification. When an entity extends through space or time, this fundamentally has to do with the way in which the entity is situating itself in a scheme of relatedness. The different modes of extension are part of what determines how an entity interacts, or connects with other entities. It can do this spatially or temporally, or any other numbers of ways which we cannot conceive. An entity that is highly extended is strongly related to many entities compared to one which is less extended. With this in mind, we can begin to think of time as just one form of extensive connection. The process of becoming is atemporal for Whitehead, time merely illustrates certain effects of becoming. What is more fundamental in talking about past, present, and future for Whitehead is determining the causal order of things. What we see as time merely illustrates some aspects of the causal relationships in a given entity’s becoming.
The extensive continuum also represents the potential divisibility of things. Everything on the continuum can be divided or split into parts by examination, but is found as a unified solidarity, hence continuum.
Now, what would this actually look like? The actual world of a given actual entity for Whitehead is causally in the past for that entity. That is, the entity is causally dependent on the entities in it. The things which this concresence is causally independent of are its contemporary entities. Though Whitehead is not clear on this, the way in which an entity extends temporally would determine which entities in its causal future are dependent on it and which are independent, while matters of space would deal with the “location” and importance of its connections to entities in this timeframe.
Thinking of becoming outside of time allows for a great expansion of the imagination. It lets us to reconcile notions of eternity and permanence inside of an ever-novel and changing universe, and also makes the discoveries of empirical science—like relativity, quantum entanglement, et cetera—more easily reconcileable with our categories of thought, though I am hesitant to make any sweeping claims on this matter without doing further research.