Reading from archive.com's OCRed text version of Whitehead's Process and Reality, which I've been processing into a more readable and searchable format.
Introduction section of Stengers' book "Thinking with Whitehead" is also on archive.org.
The speculative scheme of Whitehead's process philosophy is described by way of its categories: the category of the ultimate; the categories of existence; the categories of explanation; and the categoreal obligations. The purpose of the speculative scheme is to generalise from particular experiences, so that we can understand experience in general. The scheme should be "adequate for the interpretation of the ideas and problems which form the complex texture of civilized thought" and "obtain a reasonably complete account of human experience". In the end, "in so far as the enter- prise has been successful, there should be no problem of space-time, or of epistemology, or of causality, left over for discussion. The scheme should have developed all those generic notions adequate for the expression of any possible interconnection of things."
"In their natures, entities are disjunctively 'many' in process of passage into conjunctive unity. This Category of the Ultimate replaces Aristotle's category of 'primary substance'."
"Thus the 'production of novel togetherness' is the ultimate notion embodied in the term 'concrescence/ These ultimate notions of 'production of novelty' and of 'concrete togetherness' are inexplicable either in terms of higher universals or in terms of the components participating in the concrescence. The analysis of the components abstracts from the concrescence. The sole appeal is to intuition."
"The Category of the Ultimate" expresses the general principle presupposed in the three more special categories. 'Creativity', 'many', 'one' are the ultimate notions involved in the meaning of the synonymous terms 'thing', 'being', 'entity'. These three notions complete the Category of the Ultimate and are presupposed in all the more special categories."
One "The term 'one' does not stand for 'the integral number one', which is a complex special notion. It stands for the general idea underlying alike the indefinite article 'a' or 'an' and the definite article 'the' and the demonstratives 'this' or 'that' and the relatives 'which' or 'what' or 'how'. It stands for the singularity of an entity."
Many "The term 'many' presupposes the term 'one' and the term 'one' presupposes the term 'many'. The term 'many' conveys the notion of 'disjunctive diversity'; this notion is an essential element in the concept of 'being'. There are many 'beings' in disjunctive diversity."
Creativity "'Creativity' is the universal of universals characterizing ultimate matter of fact. It is that ultimate principle by which the many, which are the universe disjunctively, become the one actual occasion, which is the universe conjunctively. It lies in the nature of things that the many enter into complex unity."
Together 'Together' is a generic term covering the various special ways in which various sorts of entities are 'together' in any one actual occasion. Thus 'together' presupposes the notions 'creativity', 'many', 'one', 'identity' and 'diversity'. The ultimate metaphysical principle is the advance from disjunction to conjunction, creating a novel entity other than the entities given in disjunction. The novel entity is at once the togetherness of the 'many' which it finds, and also it is one among the disjunctive 'many' which it leaves; it is a novel entity, disjunctively among the many entities which it synthesizes. The many become one, and are increased by one.
"There are eight Categories of Existence:
(i) Actual Entities (also termed Actual Occasions), or Final Realities, or Res Verae.
(ii) Prehensions, or Concrete Facts of Relatedness.
(iii) Nexus (plural of Nexus), or Public Matters of Fact.
(iv) Subjective Forms, or Private Matters of Fact.
(v) Eternal Objects, or Pure Potentials for the Specific Determination of Fact, or Forms of Definiteness.
(vi) Propositions, or Matters of Fact in Potential Determination, or Impure Potentials for the Specific Determination of Matters of Fact, or Theories.
(vii) Multiplicities, or Pure Disjunctions of Diverse Entities.
(viii) Contrasts, or Modes of Synthesis of Entities in one Prehension, or Patterned Entities."
Actual Occasions Actual occasions of experience are proposed by Whitehead in his book Process and Reality as the “actual entities” of which the actual world is built up. They are described as “drops of experience” and as “creatures”, as “unique” and “novel advances”. Whitehead said there is no "going behind" the actual occasions to find anything more real. These actual entities are proposed as a modern rejection of the ancient Greek proposition that the actual entities are instances of “substance-quality categories”. Actual occasions are proposed as having both a “mental” and a “physical” pole (which is a deliberate rejection of the mind-body dualism from Descartes). However, “mentality” only amounts to “conscious intellectuality” in some actual occasions. They are proposed as having a "subjective aim" which is a proposition that "lures feelings" and conditions the "creativity that exists beyond the actual occasion“. The subject of an actual occasion is the actual occasion itself. Actual occasions become what they are and then perish into "stubborn facts” but don't subsequently “change”. Therefore, an actual occasion doesn’t experience itself. Whitehead suggested “atomism” is the ultimate “metaphysical truth”, and the “actual occasions” are Whitehead’s metaphysical “atoms”. They are indivisible in their subjective aim, but divisible in their physical actuality. This is Whitehead's first "category of existence”.
Actual occasions are proposed as having “four stages” (“datum”, “process”, “satisfaction”, “decision”). The later stages depend on the previous stages. The first stage is called "datum" and amounts to the "subjective objectifications" (or "feelings" or "processes of appropriation") which are the relations from one actual occasion to previous ones. It's necessarily "stratigraphic", a directed acyclic graph, since it isn’t possible to relate to something that doesn’t exist (or hasn’t happened), and an actual occasion isn’t something until it has become whatever it will be. The second stage is called "process" and "answers the question of what the actual occasion will be”. The datum is adjusted through this process, by positively including some actual occasions, and negatively eliminating others, until a harmony or settlement or unity is reached. The unity makes the occasion what it is. This settlement is the third stage. The fourth stage is the physicality actuality of the occasion, the settlement as physical actuality in the settled world beyond itself.
Feelings (aka Prehensions)
Nexus (aka Event) A nexus has actual occasions as "members", so I reckon it's a least a bit like a set. But there are different types, that are characterised by their degree of order. Whitehead says that an actual occasion is the "limiting type" of a nexus with only one member. Obviously there isn't any scope for different orderings of only one thing. A nexus that has one occasion followed by another is an event that is definitely not an actual occasion. Like "dual writes" it isn't atomic in its subjective aim, since there are two of them. A nexus either has "social order" or it doesn't. For a nexus to have social order, there must be a "fact of togetherness" shared by the actual occasions that are members of this nexus. Without a fact of togetherness, the nexus is a non-social nexus, and Whitehead says this corresponds to the notion of "chaos". If the actual occasions are ordered serially, the "social order" is a "personal order". A social nexus is a society of events, and a society that has many strands of personal order is called a "corpuscular society". The physical enduring objects we encounter is the real world are all societies of events.
Subjective Forms
Eternal Objects
Propositions
Multiplicities
Contrasts
Change the contrast between successive actual occasions
World the world is a process...
Enduring physical object undergoes "adventures of change"
Living person conscious intellectuality as high grade of mentality