In this chapter, I explore the connections between Whitehead's metaphysical theory and contemporary cosmology by examining his theory of extension. This involves the most general features of structure in the universe that are addressed in his later process ontology. I also continue to explore the issue raised in Chapter 4 concerning the emergence of gross physical bodies and the entire extended universe from the foundation of events. As Whitehead's theorising becomes increasingly general, his account of how our universe began provides a basic framework for a comparison with contemporary multiverse speculation. This then raises the question about the scientific status of this hypothesis.

WHITEHEAD'S THEORY OF COSMIC EPOCHS

In Process and Reality ([1929] 1978), subtitled An Essay in Cosmology, Whitehead advanced a cosmology as part of his general metaphysics of process. Metaphysics is the philosophical enquiry into the most general principles of reality. As he says it is ‘the science which seeks to discover the general ideas which are indispensably relevant to the analysis of everything that happens’ ([1926] 1996: 84) whereas cosmology is ‘the effort to frame a scheme of the general character of the present stage of the universe’ ([1929] 1958: 76). Metaphysics therefore seeks principles that are necessary for any possible world or cosmic epoch while cosmology discovers by observation what happens to be the case about our actual world or this cosmic epoch.

As part of his metaphysics, Whitehead formulated a mereological theory that he called ‘the theory of society’. This theory of whole-part relations accounts for the order of nature in the extensive continuum. As we saw in Chapter 4, he used the general term ‘nexus’ to designate a special togetherness of the basic entities of his system. Some nexū s (plural of nexus) are purely temporal or spatial, for example, consciousness and interstellar space. A ‘society’ is a macroscopic object. It is a nexus that has what Whitehead calls ‘social order’.