Metaphysics often faces undue criticism. “Many people consider it a waste of time,” states philosopher Stephen Mumford from Durham University, UK, and author of Metaphysics: A Very Short Introduction. “Are they simply arguing over trivial matters, like how many angels can dance on the head of a pin?”

This viewpoint is understandable. Classical metaphysics—originating from the Greek term “meta”—has often grappled with peculiar questions. For instance, what constitutes a table? What shape does color assume? We utilize logical tools like “reductio ad absurdum” to derive conclusions solely from inference. This method seeks to demonstrate the validity of a claim by highlighting absurdities within its negation, quite different from the empirical observations that characterize scientific inquiry.

Nonetheless, the notion that metaphysics is merely an abstract discipline disconnected from reality is rebutted by Mumford:

Indeed, modern science has encroached upon areas once deemed exclusive to metaphysics, including the nature of consciousness and the implications of quantum mechanics. It’s becoming increasingly evident that both domains are interconnected.

To understand this interplay, one must recognize that everyone inherently possesses metaphysical beliefs, asserts Vanessa Seyfert, a philosopher of science at the University of Bristol, England. For instance, many believe in the existence of objects even when they are not being observed, despite the absence of robust empirical evidence to support this claim.

Moreover, “naturalized metaphysics” emerges from this discussion. Unlike traditional metaphysics, which remains speculative, this version is grounded in scientific understanding, according to Seyfert. “We observe what science reveals about our universe and consider whether we can accept it as literal truth.”

This contemporary metaphysics serves a crucial role for science, as it probes the foundational assumptions behind our understanding of the universe. “In many instances, metaphysical beliefs form the basis upon which empirical knowledge is constructed,” explains Mumford.

Causality—the principle that every effect has a cause—is a prime example. Despite the fact that causality itself is not directly observable, it is a belief we universally hold. “Essentially, the entirety of science operates on this metaphysical premise of causality,” he remarks.

These days, scientists routinely engage with deeply metaphysical concepts, ranging from chemical elements to space and time, as well as the very laws of nature, thereby intensifying the scrutiny of these ideas.

“We can critically evaluate our metaphysical assumptions or choose to overlook them for their validity,” says Mumford. “However, ignoring them means we make unexamined assumptions.”

One notable intersection of science and metaphysics exists in quantum mechanics, which delves into the atomic and subatomic realm. While it stands as a highly successful scientific framework, addressing its implications requires physicists to confront metaphysical queries, such as the interpretation of quantum superpositions.

In this realm, competing interpretations of reality exist without being testable through conventional experiments. It’s increasingly clear that scientific advancement hinges on confronting these hidden assumptions. In response, some researchers are revitalizing the notion of “experimental metaphysics,” aiming to assess the consistency of metaphysical beliefs that prioritize various interpretations of quantum theory.

“Ultimately, you cannot engage in physics without also grappling with metaphysical inquiries,” states Eric Cavalcanti, a prominent proponent of this perspective at Griffith University in Brisbane, Australia. “Both aspects must be addressed simultaneously.”