Quantum Processes: A Whiteheadian Interpretation of Quantum Field Theory (review)

Many philosophers and physicists—including the current reviewer—have argued that Whitehead's process philosophy provides a conceptual framework better suited for understanding the quantum theoretical account of the atomic domain than does the substance ontology that has dominated Western metaphysics. However, apart from calling attention to this issue, few (with the notable exceptions of Henry Stapp and Jorge Nobo) have attempted to do anything about it. Frank Hättich has now changed this situation by providing a sustained analysis of quantum field theory (QFT) in terms of Whitehead's ontological scheme. The result is interesting for two reasons: (1) by extending the match between Whitehead's specific metaphysical proposals and the mathematics of algebraic QFT to a level of detail never before attempted, Hättich greatly strengthens the hope that process ontology can help resolve quantum mysteries; and (2) in noting the points of noncompatibility between QFT and Whitehead's metaphysical conclusions, he suggests ways of revising Whitehead's pioneering effort to enhance the match between speculative ontological scheme and contemporary physical theory.

Hättich's book is in three unequal parts: the first two are exegetical, and the third, constituting nearly half the book, is synthetic. Part I presents a "simplified version" of those parts of Whitehead's ontology pertinent to the interpretation of QFT to be presented, and Part II presents an algebraic formulation of QFT susceptible to that interpretation. Although Part I is "self-contained" from the point of view of its intended application, it is unlikely that a reader wholly ignorant of Whitehead's process ontology would gain enough enlightenment to appreciate much of the author's argumentation; but it is equally unlikely that such a person would be reading this book. Part II presumes considerable mathematical sophistication and familiarity with the formalism of at least quantum mechanics and some knowledge of field theory. It is "introductory" only in the sense that it introduces the particular version of QFT, algebraic QFT (AQFT), to which process ontology is to be applied.

Of course, both Whitehead's metaphysics and quantum theory have been subjected to many and various rival interpretations, and in selecting among them Hättich has clearly, and reasonably, been led by choices that maximize the connections he wishes to explore. It is misleading to see the goal here as developing yet another argument for why quantum theory must (or must not) be interpreted realistically. Rather, this investigation presupposes a realist interpretation and then gets to work constructing an ontological framework to show how this is possible, thereby suggesting that those who have argued that a realist interpretation of quantum theory is conceptually impossible have done so because they remain committed to ontological presuppositions moored in classical physics.

In presenting the ontological framework for his project in Part III, Hättich accounts for the process of each occasion's creative concrescence from pure potentiality to determined actuality in terms of three Whiteheadian concepts: (1) the extensive continuum; (2) eternal objects; and (3) the underlying activity. Each one of these ontological elements is then matched up with an aspect of the mathematical formalism by which AQFT represents the quantum state of a region in spacetime. Hättich then shows that given these identifications, various consequences of the mathematical formalism imply that some of the ontological claims made by Whitehead are either inconsistent or incompatible with the presumption that AQFT gives us a true account of the world. Thus although the final conclusions of this investigation are critical of Whitehead's specific metaphysical conclusions, the extent of the applicability of his ontological categories to quantum mechanics and QFT provides persuasive grounds for hoping that future realist interpretations of quantum theory can learn much from process metaphysics. For this reason, Hättich is to be commended for keeping the project of process ontology alive by proposing specific reasons for revising Whiteheadian conclusions based on our best scientific theories of the microdomain, rather than arguing...