Is event ontology forced on us by modern physics?

Book review:
The Event Universe:  The Revisionary Metaphysics of Alfred North Whitehead
by Leemon McHenry

The idea that the world consists of objects that persist through time (what this book calls “substance ontology”) comes naturally to us.  The author, Leemon McHenry, thinks this is largely because of the way our grammar is structured and argues that modern physics suggests something different, something more like Whitehead’s “event ontology”.  I have found Alfred North Whitehead’s own writings very difficult to follow, at least without consulting books of his interpreters who explain the jargon, and McHenry does a good job of briefly and clearly making the main points.  Whitehead’s metaphysics is reminiscent of supersubstantivalism, the idea that spacetime is the only thing that exists, and every other quality (mass, charge, etc) is just a property of parts of spacetime.  Event ontology further stipulates an atomist doctrine that only individual points of spacetime (events) are ultimately real; spacetime itself is just an aggregate of events.  Actually, Whitehead seems to think that the manifold picture of spacetime breaks down at some level and spacetime is ultimately cellular, and these individual cells Whitehead calls “actual occasions” and regards as the ontologically fundamental beings.  In this picture, continuity through time, whether of an atom or a person, is an illusion.  At most, a timelike sequence of actual entities may resemble each other and be causally related.  It’s quite remarkable that the world can be described either by things with properties or by spacetime events with properties, and the event picture is impressively clear and simple.

How does modern physics force such a view on us, especially given that physicists themselves frequently speak of particles or fields enduring through time?  I did not find the arguments for this clear or compelling.  The author points to ways that physics has undermined belief in other theoretical constructs such as action at a distance between point particles, absolute time, point particles of completely localized position, a continuum of atomic orbits, and so forth, but does not establish that the notion of substance relies on any of these.  After all, Newtonian and Aristotelian physics already admit extended bodies, and they already live in a continuous spacetime built from 1D and 3D manifolds (as product space in Aristotelian physics, as fibre bundle in Galilean/Newtonian) on which fields could live, but they are thought to accommodate substances without problem.  Timelike worldlines certainly seem to describe paths of objects persisting for finite time.  Bertrand Russell’s argument reported in this book that we directly observe events but not substances is also unconvincing.  It is only true if he means observation events, in which case we are on the road to solipsism, but a single observation event need not result from a single emission event and often does not.

McHenry’s job is made more difficult by Whitehead’s own wars of choice, as I think of them since they are not demanded by event ontology, with modern physics.  His cellular view of spacetime disagrees with the smooth manifold presupposed by general relativity and quantum field theory.  If the cells are sufficiently small, they would be unobservable, and some physicists do anticipate that something of the sort happens at the Planck scale, but I don’t think anyone should demand that philosophers accommodate themselves to a physical theory that doesn’t even exist yet.  Second, there is Whitehead’s rejection of eternalism, meaning he accepts either presentism or a growing block universe, either of which requires a favored foliation of spacetime into surfaces of simultaneity, which would contradict relativity (or at least introduce extraneous, unobservable entities).  McHenry realizes this is a problem (more clearly, it seems, than Whitehead did), but his suggestion for rescuing the growing block universe, of having favored spacelike hypersurfaces which are not t=constant surfaces, will not help.  It is the same thing as having favored t=constant hypersurfaces, but just in a different coordinate system, i.e. with a different favored time.  Lastly, Whitehead believed that the laws of physics are only valid in our current “cosmic epoch”, and that Maxwell’s equations in particular are slowly breaking down.  Needless to say, there is no evidence for any such violations, and the idea that the ultimate laws of physics gradually stop working and start being replaced by others is inimical to the whole enterprise of physics.  McHenry admits that the reason physicists are not open to such a possibility is because quantum field theory is currently understood and applied within an implicit substance ontology, in which fields persist through time with fixed natures.  So it seems that substance ontology accommodates itself to modern physics rather easily after all.

I have spent most of this review arguing with the book, but I quite liked it, and the author has rendered a valuable service giving an accessible and short account of Whitehead’s metaphysics and its relation to modern physics.  It also contains a polemic against restricting philosophy to the analysis of human language and concepts, which I have not discussed because I agree with it.  Whitehead himself has accomplished something extremely rare–concocting a metaphysical system very different from Aristotle’s.  It has the virtue of being very clear about what its fundamental entities are and how to identify them, while Aristotle and his followers are discouragingly vague about their substances.  I do not agree that modern physics forces us to accept event ontology, but neither does modern physics present any problems for such an adoption.  As I said, Whitehead’s own quarrels with the physics of his day and ours do not seem to be required by event ontology itself.  One could easily drop “cosmic epochs” and growing block universes while leaving events one’s only fundamental entities.