Whitehead’s theory of the physical universe is unique in the history of philosophy, and for this reason difficult to comprehend. His attempt to provide a cosmology was a major concern from his earliest work in mathematical physics inspired by Maxwell’s theory of the electromagnetic field and Einstein’s theory of relativity. Beginning with “On Mathematical Concepts of the Material World” (1905) to the view finally expressed in Process and Reality (1929), one finds a progressive refinement of his theory of extension. Once the ancient trinity of space, time and matter, along with the idea of one cosmic temporal order, was replaced by the four-dimensionality of the theory of relativity, Whitehead’s task was to explain space-time from the happenings of basic events. A major change of view occurs when he discovers that process is the fundamental idea and the extensiveness of space derivative.
In this chapter I provide an elementary exposition of the development of Whitehead’s view of objectivity and his theory of extension, with particular focus on explaining how macroscopic objects of ordinary perception and the whole structure of space-time arise out of the units of his ontology, namely, the actual occasions. I will also review the scholarship on Whitehead’s view of extension and discuss the major problems that arise in connection with the theory in Process and Reality.
1. Historical Perspective
The essence of Whitehead’s theory of the physical universe is perhaps best grasped in connection with the affinities and contrasts with the founders of the seventeenth-century cosmology, i.e., Galileo, Descartes, and Newton. They advanced the doctrine of mechanistic materialism, the clock-like view of the universe as matter in motion. The centerpiece of this view is the independence of space and time as defined by Newton in the Scholium of his Philosophiae Naturalis Principia Mathematica (1687). Objects in motion are therefore understood within a three-dimensional arena existing at different times. As Newton defined time in his Principia, he writes: “Absolute, true, and mathematical time, of itself, and from its own nature flows equally without regard to anything external […].” “Absolute space,” he said, “in its own nature, without regard to anything external, remains always similar and immovable.” As time advances from one instant to another, the whole universe is conceived to exist at once, complete and determinate. This is the concept of the cosmic now or absolute present.
A concept of absolute time and space implies that the temporal and spatial relations among objects are external. This means that the spatio-temporal relations have no effect on the essential nature of the things in space and time. On this score, Newton’s view is sometimes called the “billiard-ball model” of the universe.
Both Galileo and Newton held variations of the old doctrine of atoms and the void revived from the ancient Greek philosophers, Democritus and Epicurus. Space is a receptacle for matter in motion, they believed, since bodies can move only when there is a void that allows their passage by giving way and offers no resistance. Newton makes his view clear in his “De gravitatio et aequipondio fluidorum” when he defines the terms “place,” “body,” “rest,” and “motion” in opposition to Descartes’ view, such that: (1) space is given as distinct from body, and (2) motion is determined with respect to the parts of space, instead of positions of contiguous bodies. Extension, for Newton, is understood to be neither substance nor accident; nor is it “simply nothing” but “it has a certain mode of existence proper to itself which suits neither substances nor accidents.” By contrast, Descartes had argued against the void by conceiving of the extended universe as one physical substance having the properties of motion, divisibility, mutability and flexibility. Descartes makes the point in his Principles of Philosophy (1644) as follows:
As regards a vacuum in the philosophical sense of the word, i.e. a place in which there is no substance, it is evident that such cannot exist, because the extension of space or internal place, is not different from that of body. For, from the mere fact that a body is extended in length, breadth, or depth, we have reason to conclude that it is a substance, because it is absolutely inconceivable that nothing should possess extension, we ought to conclude also that the same is true of the space which is supposed to be void, i.e. that since there is in it extension, there is necessarily also substance.
In this way, space and bodies in space are thought of as a matter of degree rather than of kind, as thin and thick regions of extension. According to Descartes, space or extension is a plenum.
The mechanistic theory together with advances in mathematics seemed securely on the path to unlocking the secrets of nature. At almost every step of the way for succeeding generations, all parts of the physical puzzle appeared to come together ultimately confirming Newton’s grand cosmological scheme. With the revolution in physics that occurred with Einstein’s special and general theories of relativity, however, it was clear that the whole foundation of physics needed rethinking. As Whitehead says in the Preface to The Principle of Relativity, his alternative rendering of the theory of relativity “takes its rise from that ‘awakening from dogmatic slumber’—to use Kant’s phrase—which we owe to Einstein and Minkowski” (R, v)
Whitehead opposed the doctrine of mechanistic materialism on every point. First, as opposed to the mechanical conception of the universe, Whitehead’s view of reality is more thoroughly organic (SMW, 75). From the beginning of his foray into philosophy, he had in mind a unification of biological and physical phenomena. Second, in contrast to the absolute theory of space and time, he advanced a relative theory following Leibniz and Einstein. Third, in place of the primacy of instants of time and points in space, Whitehead argues that all perception of nature occurs within durations. Fourth, the theory of substance or the materialist doctrine underlying the seventeenth-century cosmology is replaced with an ontology of events. Process replaces substance as the basic idea. Fifth, as Whitehead’s theory evolves, his understanding of events is refined such that the basic entities are conceived as atoms of experience. This, he claimed, is a repudiation of the doctrine of “vacuous actuality” (PR, xiii).
2. Pan-Physics and Four-Dimensionality
The three books of Whitehead’s middle period, The Principles of Natural Knowledge (1919), The Concept of Nature (1920) and The Principle of Relativity (1922), attempt a unification of the natural sciences, or a “pan-physics” based on the theory of events (R, 4). He writes: “Modern speculative physics with its revolutionary theories concerning the natures of matter and of electricity has made urgent the question, What are the ultimate data of science?” (PNK, v). The main trouble with the ontology of the classical view, according to Whitehead, is that it does not stand up to empirical examination. His task therefore is to replace this view with one that advances the interconnection of events discriminated in perceptual experience. He then builds up the extended physical universe from this new foundation.
Instants of time and points of space quite simply do not appear in our experience of nature. They are abstractions of thought falsely believed to be the basic entities of the extended universe. Events, however, he argues are known in durations of immediate experience and each event is essentially a quantum of extension that is both spatially and temporally thick. Extension, at this point in Whitehead’s system, is the primary feature of actuality, and the basic relational property is the whole-part relation of “extending over.” He writes: “Every event extends over other events, and every event is extended over by other events” (CN, 59). By inference, we construct the total picture of nature, inwards and outwards, by the doctrine of “significance” which explains the interconnected network of events. In this way, we understand how events form a uniform structure from the inside of an atom to the galaxies beyond the Milky Way. Within events we discriminate “objects” which are repeatable characters discerned within events. As Whitehead puts it, objects are the “recognita amid events” (PNK, 81). The repetition of objects in events is what makes science possible. The discovery of the laws of nature, for instance, is due to the fact that the characters of events repeat themselves in some fairly stable fashion (PNK, 87). The theory of periodicity crucial to the mathematical analysis of nature finds its basis in this important aspect of objects. Whitehead distinguishes three kinds of objects: “sense-objects” such as individual colors, “perceptual objects” such as ordinary macroscopic objects, and “scientific objects” such as electrons and molecules (CN, 149). “Things” as we ordinarily understand them, are relatively monotonous patterns in event sequences. They are bundles of energy that more or less maintain their characteristics and consequently form “space-time worms” (or following Minkowski, “world-lines”) in the four-dimensional manifold.
The doctrine of significance is Whitehead’s replacement of the theory of external relations. The central feature of an event is its relatedness within a system of whole-part relations forming the entire system of the extended universe. It is not what it is in isolation, but has its existence only as a part of a network. This doctrine also plays an important role in the relational theory of space because instead of conceiving things as first in space and then as acting upon one another, the theory of significance requires us to think of space-time as arising out of the relations of events.
When Whitehead now considers the problem of the geometry of space-time, he constructs instants, points, lines, planes, and volumes from his method of extensive abstraction—the logico-mathematical procedure of deriving such abstractions by a progressive narrowing of events from immediate perception. The resulting structure is a geometry of the four-dimensional manifold. A central feature of this theory is the notion of stratified time-systems within space-time. This sets up the basis for his explanation of the relative motion of objects. A frame of reference occurs within one time-system constructed from what Whitehead calls a “family of parallel durations.” The indefinite number of families of parallel durations constituting different time-systems is one of the main distinguishing features of the theory of relativity. By contrast, there is only one absolute time-system in the Newtonian theory (PKN, 113; CN 190). Whitehead’s system agrees with the Einstein-Minkowski formulation of relativity theory in that there is no unique cosmic “Everywhere-Now” or absolute simultaneity.
Whitehead’s view of extension here approximates Descartes’ concept of the plenum in that both reject the very idea of empty space (PR, 73). In accordance with Einstein, however, space is fused with the fourth dimension of time. So-called empty space is, for Whitehead, a uniform electromagnetic field including the vast regions between planets and galaxies and the vast regions between subatomic particles in the atom (here understood as objects ingredient in event structures). The alternative theory proposed by Whitehead differs most from Einstein in that Whitehead argued for a uniform structure of space-time constructed from his ontology of events. Einstein held that the structure of space-time varied with its contents because of the peculiarities in the distribution of matter throughout the universe; the presence of matter distorts the uniform space-time structure and results in a curved space-time. But since Whitehead rejected the traditional concept of matter and substituted this with the concept of objects ingredient in events, the space-time of perception is conceived as continuously uniform with the more refined space-time of scientific objects.
3. The Metaphysics of Process
In Note II to the second edition of The Principles of Natural Knowledge, Whitehead said of the first edition that:
The book is dominated by the idea […] that the relation of extension has a unique preeminence and that everything can be got out of it. During the development of this theme, it gradually became evident that this is not the case, and cogredience […] had to be introduced. But the true doctrine, that ‘process’ is the fundamental idea, was not in my mind with sufficient emphasis. Extension is derivative from process, and is required by it (PNK, 202).
This is the beginning of Whitehead’s excursion into a much more comprehensive system of nature.
Contrary to much of traditional metaphysics, easily ridiculed as grandiose armchair speculation detached from scientific advance, Whitehead sees metaphysics as a generalization from the special sciences. This I have identified as “naturalized metaphysics” as opposed to “pure metaphysics.” The former involves no attempt to defend metaphysics as a discipline that has some special grasp of truth apart from scientific investigation. Rather, it accepts science as a starting point and risks its dignity in the revisable and fallible manner of hypothetico-deductive systems. Whitehead sought the most general principles from advancing knowledge in physics, biology and psychology in what he calls the “philosophy of organism” (PR, xi). In fact, his whole project in Process and Reality was to make coherent the diverse and fragmentary theories of the special sciences, including evolution, genetic inheritance, psychology, electromagnetic phenomena, quantum phenomena and relativity via general metaphysical principles of process and creative advance.
Since “process” replaces “extension” as the basic idea in his metaphysics, Whitehead’s conception of nature undergoes radical revision; the holistic conception of events interconnected by whole-part relations is developed into a pluralistic temporal atomism. In other words, the geometrical and primarily spatial thinking of his earlier preoccupation with relativity gives way to a theory that takes time seriously. This does not mean that Whitehead abandoned relativity for his new system, but modifications were necessary to reconcile relativity with temporal becoming.
In the transitional theory of Science and the Modern World and in the fully-developed metaphysics of Process and Reality, the dualism of events and objects is replaced by “actual occasions” and “eternal objects” which function more or less as particulars and universals. Actual occasions are micro-events or atoms of becoming that synthesize their immediate predecessors to create novel entities. Eternal objects are “Pure Potentials for the Specific Determination of Fact, or Forms of Definiteness,” Whitehead says in his “Categoreal Scheme” of Process and Reality (PR, 22). The relationship between these two pairs of entities is a difficult problem to sort out. But aside from the addition of the subjective nature of actual occasions, the important point to bear in mind is that an event becomes a nexus of actual occasions in the metaphysics. The nexus is a succession of actual occasions forming our experience of continuity and change in ordinary perception. What we perceive as change is the differences between the individual characters of occasions forming such an event.
Since the subjective character of the actual occasions has been the focus of the preceding chapter, I shall discuss the aspects of occasions that result in the solidarity of the world. Whitehead’s central task is to explain process, change and novelty. All actualities are more or less creative via the prehensive activity of actual occasions. Each creates itself from its own subjective aim. In the beginning of the concrescent process, an actual occasion inherits the eternal objects that are given from the past. If the occasion has a “dominance in its physical pole,” there is simply a brute inheritance of the same data presented by the immediate past and the occasion terminates in what Whitehead calls “physical purposes” (PR, 184). In other words, while the occasion is a new creation, the amount of novelty it contributes is negligible. Occasions of this sort make up the vast regions of space-time or the things identified in perception as inert matter or low-level organisms. But as occasions become more and more sophisticated in higher-level organisms or in consciousness, there is more opportunity for originality. Such an occasion has what Whitehead calls a “dominance in its mental pole,” i.e., the opportunity of introducing novelty into the world via conceptual feelings of a new eternal object that becomes integrated with the inherited physical feelings.
Once an occasion completes its concrescence, it contributes its data to future occasions and perishes. What the occasion contributes at its “satisfaction” is an “object” or “superject.” Whitehead is using the term “object” here to refer to what becomes public fact at the outcome of an occasion’s concrescent process. An object in this sense is what is perceived in the immediate past and is prehended as a unity by a present occasion. So, just as the light received from a star is originating from an object that might in fact be long gone, any perception of an object in the immediate present involves the transmission of light from an event in the past of the perceiver’s experience. Instead of taking years, as in the case of a distant star, in ordinary perception it occurs in a fraction of a second. The idea that the perceived object is never a contemporary one can be generalized for all actual occasions in the sense that the genetic process of concrescence involves the prehension of what is completed by the immediate past occasion just before it perishes.
The crucial task of Whitehead’s theory of extension in Process and Reality is to explain how the microscopic actual occasions form the base of enduring things of perceptual experience—rocks, plants, animals, planets, stars, galaxies and the whole structure of space-time within what he calls our “cosmic epoch” and beyond. He retains the idea of space as a plenum and explains the structure of extension via a corpuscular theory of “society.” Actual occasions form societies by their prehensions of a common complex eternal object. These are typically aggregates of mutual contemporaries with common lines of inheritance. Whitehead defines a “society” as follows:
A nexus enjoys ‘social order’ where (i) there is a common element of form illustrated in the definiteness of each of its included actual entities, and (ii) this common element of form arises in each member of the nexus by reason of the conditions imposed upon it by its prehensions of some other members of the nexus, and (iii) these prehensions impose that condition of reproduction by reason of their inclusion of positive feelings of that common form (PR, 34).
Our observations and theoretical models from physics, chemistry, biology, astronomy, cosmology, etc., explain how societies are arranged into various levels of organisms and environments or systems within systems. In this manner, we have societies of societies of societies forming subatomic particles, atoms, molecules, cells, bodies, planets, stars, solar systems, galaxies, cosmic epochs and beyond.
Whitehead makes the transition from the microscopic world of actual occasions to the macroscopic world of our perceptual experience by his notion of “transmutation,” whereby occasions in any particular physical body are prehended as a unity. When we perceive any macroscopic entity, he argues that we prehend an aggregate of many occasions as one final unity. An individual is discerned in the mass of actual occasions present to consciousness by the way the perceiver integrates the many members of the society and produces one transmuted feeling. This is possible because the members of the society share a certain dominance of characteristics or the identity of pattern of the ingredient eternal objects.
Societies can be simple or vastly complex. The simplest ones are those with “personal order,” in which the members are ordered serially. The most specialized cases of these societies are the routes of electronic or protonic actualities. Electrons and protons are societies that form the first level of physical activity (now quarks and leptons, unknown in Whitehead’s time). In laboratory conditions the physicist observes effects of subatomic particles resulting from multiple interactions of events with an electromagnetic character. These societies must be conceived as the base of the hierarchy of social order “of increasing width of prevalence, the more special societies being included in the wider societies” (PR, 92). Molecules and cells are more complex societies or what Whitehead calls “structured societies;” that is, societies that include subordinate societies and/or nexūs (plural of nexus). Whitehead thus explains:
A structured society consists in the patterned intertwining of various nexūs with markedly diverse defining characteristics. Some of these nexūs are of lower types than others, and some will be markedly higher types. There will be ‘subservient’ nexūs and the ‘regnant’ nexūs within the same structured society. This structured society will provide the immediate environment which sustains each of its sub-societies, subservient and regnant alike (PR, 103).
A cell, for example, is structured in the sense that it is a society that harbors the existence of lower, more specialized societies—at one level molecules, at another atoms, and so on. So the higher society (the cell) is regnant, and functions as an environment for the lower level (the molecules), while the lower societies are subservient and function as organisms for the higher level. This reciprocity of whole and part applies throughout various levels of order in Whitehead’s theory of extension—working outward in terms of environments or inward in terms of organisms. Each special science restricts itself to investigations within some focused region of what he calls “the extensive continuum,” namely, the entire abstract system of whole-part relations.
As we reach the limits of astronomical observation, Whitehead speculates that there are three further levels of social order necessary to complete his theory of extension: societies forming “cosmic epochs,” the geometrical society and the society of pure extension. Cosmic epochs are the widest societies in which a particular set of laws of physics reign. Our expanding universe from the Big Bang to the Big Crunch corresponds to what Whitehead calls “that widest society of actual entities whose immediate relevance to ourselves is traceable. This epoch is characterized by electronic and protonic actual entities, and by yet more ultimate actual entities which can be dimly discerned in the quanta of energy” (PR, 91). What is typically called “the universe” is for Whitehead only our immediate cosmic epoch that is contemporary to other cosmic epochs, each having different types of order and different laws of physics describing that order (PR, 97). The Big Bang is merely the beginning of our electromagnetic cosmic epoch, not the beginning of the universe. We must suppose there was a preceding cosmic epoch that generated our cosmic epoch and a succeeding cosmic epoch into which ours will pass. This multi-verse of cosmic epochs is nestled within a more general structured society that is the basis for the axioms of geometry and any possibility of measurement. Whatever the dimensionality of the cosmic epochs within this geometric society, they must conform to the more general geometrical order established by this society. Beyond the geometrical society, Whitehead says “we discern the defining characteristic of a vast nexus extending far beyond our immediate cosmic epoch […] the fundamental society in so far as it transcends our own epoch seems a vast confusion mitigated by the few, faint elements of order contained in its own defining characteristic of ‘extensive connection’” (PR, 97). This he calls “the society of pure extension,” namely, the widest conceivable society, but not the final society, since “there is no society in isolation” (PR, 90).
In Part IV of Process and Reality, Whitehead presents the most general abstract features of extension. He distinguishes between cosmological and metaphysical laws. The cosmological laws apply to our cosmic epoch such as those discovered about the quantum world, weak and strong nuclear forces, gravity or the number of dimensions of space. The metaphysical laws are more ultimate and apply to all cosmic epochs such as explained in his Categoreal Scheme or by the very general features of the extensive continuum—extensive connectedness and the relation of whole and part (PR, 288). In axiomatic fashion, Whitehead states the general principles for the connectedness of extensive regions and for inclusion, the latter being defined in terms of the former. (This should be understood as Whitehead’s modification of his views on extensive abstraction in The Principles of Natural Knowledge where the relation of whole and part was primary.) He then proceeds to define the geometrical elements via the notion of extensive sets. This gives him the laws of geometry or what he calls “the investigation of the morphology of nexūs” (PR, 302). In this manner, he attempts to formulate the logical structure of the extensive continuum and the geometrical principles that constitute the geometrical society.
It should be clear that macroscopic objects and the whole scheme of extensive connection in Whitehead’s metaphysics are abstractions from the actual occasions that are fully concrete and atomize the extensive continuum. In other words, the societies are the things that endure in the temporal process but they are nonetheless derivative from the basic ontological category. This is his main difference from Aristotle, who took primary substance as the basic ontological category and viewed events as secondary or dependent. This dependency is reversed in Whitehead’s system such that societies (or what Aristotle called “substances”) are dependent on basic events and not vice versa. The tendency in philosophy and science to mistake the abstract for the concrete, he called “the fallacy of misplaced concreteness” (SMW, 51).
4. Interpretations of the Past
The problem of the past has been one of the most formidable aspects of interpreting Whitehead’s theory of extension. If, as we have maintained, physical objects are perceived as the immediate past of a concrescing occasion, then the understanding of the ontological status of the past is crucial to sorting out Whitehead’s real view. Presented quite simply, does he espouse a view that all of existence is the present becoming of actual occasions and the past exists only as objects of the present becoming? Or does he view physical reality as a growing block universe in which the past exists objectively as past? When Whitehead modified his earlier theory of a four-dimensional block view to the temporal atomism underlying the process view, he clearly advanced a view in which the future is entirely open to the creative activities of the present occasion. Yet it is unclear just exactly how this works out given his acceptance of the theory of relativity and the denial of a unique cosmic present. As he says in Process and Reality: “I shall always adopt the relativity view; for one reason, because it seems better to accord with the general philosophical doctrine of relativity which is presupposed in the philosophy of organism […]” (PR 66). And in a passage that clarifies his rejection of absolute time, he writes: “There is a prevalent misconception that ‘becoming’ involves the notion of a unique seriality for its advance into novelty […]. In these lectures the term ‘creative advance’ is not to be construed in the sense of a uniquely serial advance” (PR, 35).
According to the traditional or prevailing interpretation of commentators such as Leclerc (1958), Christian (1959), Sherburne (1966), Johnson (1976) and McHenry (1992, 2000), we are to take literally Whitehead’s claim that time is a “perpetual perishing” (PR, 29, 340). It is necessary for the past to perish in order for novelty to occur in a creative universe. Process, Whitehead says, entails loss. “The present fact has not the past fact with it in any full immediacy” (PR, 340). But “perishing” does not mean that an occasion that has completed its concrescence ceases to exist as an object; on the contrary, the perishing of subjective immediacy is the point in which the occasion becomes available as an object for successors (Johnson, 1976). Objects, however, exist only in so far as they are objects for the present concrescing subjects.
Beginning with Nobo (1974, 1978, 1986), this interpretation has been challenged by the idea that Whitehead’s real view involves the notion that the objects produced in the process of becoming of actual occasions are actual and remain so for the potentiality of every new concrescing subject. According to Whitehead’s Principle of Process, an actual occasion’s being is produced by its becoming. How an actual occasion becomes constitutes what that actual occasion is (PR, 23, 166). His Principle of Relativity likewise asserts: “it belongs to the nature of a ‘being’ that it is a potential for every ‘becoming’ (PR, 22). Nobo argues that commentators have failed to appreciate the true meaning of these doctrines, for Whitehead holds that entities are actual even if they are no longer subjectively immediate. Thus, Whitehead writes as an account for the solidarity of the universe: “To be actual must mean that all actual things are alike objects, enjoying objective immortality in fashioning creative actions; and that all actual things are subjects, each prehending the universe from which it arises” (PR, 56-57). Such passages in Process and Reality lend great support for Nobo’s interpretation. Moreover Nobo contends that Whitehead’s view is a cumulative theory of actuality. When a region of the extensive continuum becomes determinate, it remains so. In this way it can function in later occasions where the data of that entity is projected into successors. The solidarity of the universe is the reality of the past.
Lango has made a similar revisionist argument by focusing attention on Whitehead’s philosophy of time in the context of relativity theory (2006). Beginning with a distinction between “presentism” and “eternalism” as for example one finds in McTaggart’s A-series and B-series, presentism holds that only the events that are happening in the present exist, while eternalism holds that just as there is no metaphysically privileged point in space, there is no metaphysically privileged present. For the eternalist then, temporal passage is “unreal” because all events in time are eternally present or have the same ontological status in the four-dimensional manifold. As Einstein famously made the point: “[…] the past, present and future are an illusion, even if a stubborn one.” The distinction between presentism and eternalism corresponds roughly to the three-dimensional and four-dimensional views of extension, but neither captures Whitehead’s distinctive view. Lango therefore proposes to see Whitehead’s view as a third alternative, described by C. D. Broad as the “growing block universe.” On such a view, the past has real existence. Broad, for example, writes: “Whatever is has become, and the sum total of the existent is continually augmented by becoming. There is no such thing as ceasing to exist; what has become exists henceforth for ever. When we say that something has ceased to exist, we only mean that it has ceased to be present […].” Lango calls this view “past-and-presentism.” What is past and present exist, but not what is future. Past, present and future, however, are always defined relative to an actual occasion.
Lango argues that the growing block interpretation fits best with Whitehead’s view because: (1) it replaces the unique serial order of creative advance with the notion of durations (sets of actual occasions in unison of becoming) that are not uniquely serial; and (2) we would have no way of understanding Whitehead’s concept of nexus if past objects are not actual. The reality or actuality of the past provides a way of understanding how an actual occasion temporalizes extension by occupying a basic region that is mediately connected to the basic regions of temporally earlier actual occasions. Understanding Whitehead’s theory of extension requires seeing how topological properties of temporal order and metaphysical properties of extensive connection are coherently interwoven.
Whitehead’s view in Process and Reality appears to involve an inconsistency, and this is not merely a slip of terminology as in other cases where he used terms such as “interdependent” for what is an asymmetrical process. The inconsistency is substantive in that Whitehead is retaining elements of his earlier four-dimensionality while advancing doctrines of novelty and process. In other words, he held a view of the reality of temporal passage within the context of a relativity theory that denied temporal passage. The difficulty of attempting to reconcile the theory of epochal becoming within relativity theory finds a parallel in one of the greatest obstacles of achieving a grand unification of physical theory, namely, the indeterminacy of quantum theory with the determinism of the large-scale structure of gravity in relativity theory. Einstein, in fact, rejected quantum theory for this reason. Whitehead’s metaphysics suffers the same difficulty in that the indeterminacy of his theory of epochal becoming is incompatible with the determinacy of relativity theory. This is revealed in the debate on the status of the past where the traditional interpretations focus primarily on Whitehead’s theory of epochal becoming and the revisionist interpretations focus primarily on Whitehead’s theory of extension or the theory of relativity. The revisionist interpretations reveal the complexity of Whitehead’s system that has been overlooked by the traditional interpretations.
While I cannot explore these issues here in any detail, I will end by simply pointing out some difficulties for the revisionist views.
(1) When Whitehead explained time or the past as “perpetually perishing,” he appears to be speaking literally. In an essay published in 1947 in which he summarizes his view, he writes:
Almost all of Process and Reality can be read as an attempt to analyse perishing on the same level as Aristotle’s analysis of becoming. The notion of the prehension of the past means that the past is an element in the state beyond, and thus is objectified. That is the whole notion. If you get a general notion of what is meant by perishing, you will have accomplished an apprehension of what you mean by memory and causality, what you mean when you feel that what we are is of infinite importance, because as we perish we are immortal. That is the one key thought around which the whole development of Process and Reality is woven […]. (ESP 117)
(2) If the past is seen to be actual as being, we have an ontological duplication in Whitehead’s system which appears rather implausible especially as a violation of Occam’s Razor and the principle of identity. (This objection applies more directly to Lango’s view since Nobo has argued for an interpretation of Whitehead that involves repeatable particulars.) In the “Final Interpretation” of Process and Reality, Whitehead makes it clear that the past is objectively immortal in God’s consequent nature (PR 340, 351). That is, while the past is never wholly contained in the present, the past is positively prehended in the divine being, not merely as a copy of what was actual but rather as determinate being. But the past cannot exist in two places at once—in the actual past as determinate being and in the being of the divine actual entity.
(3) If the revisionist view is correct, past events remain eternally there in the past but deprived of their status as subjectively immediate. Just exactly how are we meant to envisage this realm of past events without subjectivity is puzzling at best. Like geological strata of the earth full of dinosaur bones and clay pots, the past must be seen as dead but not quite gone. But according to Whitehead’s ontological principle, everything must be somewhere in actuality. Outside of the creative activity of actual occasions, there is nothingness (PR, 19, 24). This helps us understand more fully the sorts of claims Whitehead makes regarding extension or objectivity as an abstraction from the concreteness of actual occasions. It also sheds light on the necessity of the one divine actual entity which contains the whole past world as objectively immortal. As he puts it: “the actual world is built up of actual occasions; and by the ontological principle whatever things there are in any sense of ‘existence,’ are derived by abstraction from actual occasions” (PR, 73). (4) Finally, each occasion’s becoming is a present but clearly not the present. This means there will be occasions earlier than the present becoming that will be causally objectified in it, contemporaries that will be in a unison of becoming with the present occasion and occasions that are future. While this is surely a consequence of Whitehead’s acceptance of relativity theory, it is not at all clear how this view squares with the notion of a growing block universe or the modern concept of the expanding universe. The problem is that it appears to reverse Whitehead’s discovery that extension is derivative from process because becoming happens in a pre-existing framework of extension.
 Isaac Newton, 1995, 13.
 Achinstein 1991, 156-57.
 Newton 1962.
 Newton 1962,99.
 Descartes 1931, 262.
 For a more detailed exposition of Whitehead’s philosophy of physics, see my chapter on “Pan-Physics: Whitehead’s Philosophy of Natural Science, 1918-1922,” in Lowe 1990.
 Einstein 1920, 137.
 See McHenry 1992, 16-17.
 See especially Milič Čapek, 1991, 324-343 (“Time-Space Rather Than Space-Time”).
 For a thorough explanation of the development of this transitional theory, see Ford 1984.
 See Hawking 1988, Chapter 8; cf. Greene 2004, Ch. 13 where he discusses cyclic cosmology.
 In this connection, see my 1996 article, “Descriptive and Revisionary Theories of Events.”
 McTaggart 1927, Chapter XXXIII.
 Hoffman and Dukas 1972, 258.
 Broad 1959, 66.
 I wish to thank Pierfrancesco Basile and John Lango for helpful comments on an earlier draft of this chapter.
Works Cited and Further Readings
Achinstein, Peter. 1991. Particles and Waves (New York, Oxford University Press).
Broad, C.D. 1959. Scientific Thought (Patterson NJ, Littlefield, Adams and Co.).
Čapek, Milič. 1991. The New Aspects of Time (Dordrecht, Kluwer).
Christian, William. 1959. An Interpretation of Whitehead’s Metaphysics (New Haven, Yale University Press).
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How to Cite this Article
McHenry, Leemon, “Extension and the Theory of the Physical Universe”, last modified 2008, The Whitehead Encyclopedia, Brian G. Henning and Joseph Petek (eds.), originally edited by Michel Weber and Will Desmond, URL = <http://encyclopedia.whiteheadresearch.org/entries/thematic/metaphysics/extension-and-the-theory-of-the-physical-universe/>.