Kerry McKenzie: The Limits of Scientistic Metaphysics

Kerry McKenzie sets the context by discussing previous work with Steven French on the attitudes naturalistic metaphysicians should have towards a priori or analytic metaphysics. The motivation for this work stemmed from criticisms within the philosophy of science, especially by James Ladyman, who argued that most metaphysical work was trivial and disconnected from science. McKenzie acknowledges these criticisms but points out that analytic metaphysics can be valuable as a heuristic for philosophers of science, though this view has faced criticism for being overly permissive.

McKenzie argues that while science should be central to metaphysics, a priori methods used in analytic metaphysics are still indispensable. The first part of the talk reviews criticisms of analytic metaphysics, highlighting its perceived frivolity and over-reliance on intuition. McKenzie then discusses how some metaphysicians are redefining their field to better articulate its nature, noting that this redefinition does not necessarily negate the criticisms but can lead to productive engagement with scientific concepts.

McKenzie delves into specific criticisms of analytic metaphysics, such as its reliance on intuitions to justify claims. Examples include van Inwagen's debate on composition and the role of gunk spheres in refuting rival theses. These discussions illustrate the problematic nature of using intuitions as a basis for metaphysical arguments. McKenzie also highlights the disconnect between these metaphysical debates and scientific practice, pointing out that scientific concepts often contradict metaphysical intuitions.

McKenzie examines two conceptions of metaphysics proposed by contemporary metaphysicians: Laurie Paul's view of metaphysics as a genuine discipline and E.J. Lowe's idea of metaphysics as the science of the possible. McKenzie critiques Paul's view for its a priori approach, arguing that meaningful engagement with science is crucial. For Lowe's view, McKenzie contends that ignoring science undermines the project of understanding possibility, as scientific insights can refute purely metaphysical principles.

McKenzie argues that if metaphysics is to provide a general account of categories like objects and properties, it must engage with scientific theories. Using examples from physics, McKenzie shows that metaphysical theories about categories often need to be vague and non-committal to remain true across different scientific contexts. This vagueness limits the usefulness of purely a priori metaphysical projects, emphasizing the need for collaboration with scientific disciplines.

McKenzie discusses the concept of fundamental properties in the context of quantum field theory. She argues that fundamental properties are not intrinsic and depend on the presence of other fields in the theory. This interdependence challenges the notion that fundamental properties can be defined a priori. McKenzie suggests that paying attention to physics can reveal the limitations of purely metaphysical theories, reinforcing the need for scientific engagement.

McKenzie explores David Lewis's modal realism and its reliance on the principle of recombination, which requires fundamental properties to be intrinsic. She argues that the interdependence of properties in quantum field theory undermines this principle. This example illustrates how physics can falsify metaphysical theories, highlighting the indispensability of scientific input in metaphysical inquiries into possibility.

McKenzie examines the concept of fundamentality, critiquing the modal analysis commonly used in metaphysics. She argues that this analysis fails to account for the complexities of physical theories. McKenzie points out that debates over fundamentality in philosophy of physics often rely on intuitions, which are also used in analytic metaphysics. She suggests that resolving these debates requires a nuanced approach that integrates scientific insights.

McKenzie discusses ontic structural realism, which posits that relational structures are more fundamental than objects. She argues that purely modal analyses of fundamentality cannot support this view, as they fail to capture the nuances of physical theories. McKenzie suggests that grounding and detailed analysis of scientific theories are necessary to substantiate claims about fundamentality, demonstrating the importance of scientific engagement in metaphysical discussions.

McKenzie explores the relationship between scientific theories and metaphysical concepts of fundamentality. She argues that scientific insights can challenge and refine metaphysical theories, using examples from quantum mechanics and gauge theories. McKenzie emphasizes that understanding fundamentality requires a detailed engagement with science, as purely a priori methods are insufficient to capture the complexities of physical reality.

McKenzie discusses the method of reflective equilibrium, which seeks a balance between intuitions and theoretical considerations in metaphysics. She argues that intuitions play an indispensable role in analyzing concepts like fundamentality, but these intuitions must be informed by scientific theories. McKenzie suggests that philosophers of physics must engage deeply with scientific concepts to develop robust metaphysical theories.

McKenzie concludes by emphasizing the need for a nuanced and integrative approach to metaphysics that acknowledges the indispensability of scientific engagement. She argues that a purely a priori metaphysics is insufficient to address the complexities of modern science. Instead, philosophers must be willing to revise their intuitions and theories in light of scientific developments, fostering a productive dialogue between metaphysics and science.

McKenzie responds to criticisms of her approach, addressing the challenges posed by the complexities of quantum mechanics. She argues that metaphysicians must engage with scientific theories, even when they are difficult to understand, to develop meaningful metaphysical concepts. McKenzie suggests that this engagement can lead to a more accurate and comprehensive understanding of fundamental properties and the nature of reality.

McKenzie acknowledges that while quantum mechanics is complex, other scientific disciplines like biology and chemistry can also provide valuable insights for metaphysical theories. She suggests that metaphysicians should look beyond fundamental physics and engage with a broader range of scientific fields to develop a more comprehensive understanding of metaphysical concepts.

McKenzie addresses the concern that metaphysical theories should not rely too heavily on current scientific theories due to the possibility of future scientific revolutions. She argues that naturalistic metaphysics must still engage with the best available science, even if it evolves. McKenzie suggests that metaphysicians should be adaptable and willing to revise their theories in response to new scientific developments.

McKenzie emphasizes the importance of engaging with scientific interpretations and the need for metaphysicians to understand the formalism and principles underlying scientific theories. She argues that metaphysical debates must be informed by the latest scientific developments to remain relevant and accurate.

McKenzie discusses the interplay between metaphysics and physics, arguing that metaphysical theories often rely on principles derived from classical physics. She suggests that metaphysicians must be aware of the limitations of these principles and be open to revising their theories in light of new scientific insights, particularly from quantum mechanics and other advanced fields.

McKenzie concludes by advocating for a broad engagement with various scientific disciplines to enrich metaphysical theories. She argues that insights from biology, chemistry, and other fields can provide valuable perspectives that help refine and validate metaphysical concepts. McKenzie suggests that metaphysicians should embrace a collaborative approach with scientists to develop a more comprehensive and accurate understanding of reality.