This module contains three base classes, which distinguish between “actual occasion” (which “domain model event” is an example of) and “enduring object” (which “domain model aggregate” is an example of). These terms “actual occasion” and “enduring object” are taken from Alfred North Whitehead’s Process and Reality (published 1929). The base classes both inherit from a base class “event” because, in Whitehead’s system, an enduring object is an event, and so is an actual occasion.

class eventsourcing.whitehead.Event[source]

Bases: object

“I shall use the term ‘event’ in the more general sense of a nexus of actual occasions, inter-related in some determinate fashion in one extensive quantum. An actual occasion is the limiting type of an event with only one member.”

Alfred North Whitehead, 1929

class eventsourcing.whitehead.ActualOccasion[source]

Bases: eventsourcing.whitehead.Event

“‘Actual entities’ – also termed ‘actual occasions’ – are the final real things of which the world is made up. There is no going behind actual entities to find anything more real.”

“Just as ‘potentiality for process’ is the meaning of the more general term ‘entity’ or ‘thing’; so ‘decision’ is the additional meaning imported by the word ‘actual’ into the phrase ‘actual entity’. ‘Actuality’ is the decision amid ‘potentiality’. It represents stubborn fact which cannot be evaded.”

“Actual entities perish, but do not change; they are what they are.”

Alfred North Whitehead, 1929

class eventsourcing.whitehead.EnduringObject[source]

Bases: eventsourcing.whitehead.Event

“The notions of ‘social order’ and of ‘personal order’ cannot be omitted from this preliminary sketch. A ‘society’ in the sense in which that term is here used, is a nexus with social order; and an ‘enduring object’ or ‘enduring creature’ is a society whose social order has taken the special form of ‘personal order.’”

“A nexus enjoys ‘personal order’ when (a) it is a ‘society’ and when the genetic relatedness of its members orders these members ‘serially’.”

Alfred North Whitehead, 1929