A University of Saskatchewan physicist argues that spacetime does not exist as a physical entity but serves as a model for describing events. Treating events as existent objects leads to philosophical confusion and misconceptions like time-travel paradoxes. This view aims to bring clarity to physics and philosophy by distinguishing happenings from existing things.
Daryl Janzen, a physicist at the University of Saskatchewan, challenges the common perception of spacetime in a recent article. He contends that spacetime is not a real, physical entity but a human-centered framework, akin to the outdated concept of a celestial sphere, used to describe and organize observations without representing reality's underlying nature.
Janzen explains that events are not locations or objects that exist; they simply happen. This distinction is crucial, as fictional depictions of time travel and philosophical theories often treat past and future events as revisitable places. He critiques views like eternalism, where all events across time exist; the growing block theory, where past and present exist while the future emerges; and presentism, where only the present exists. General relativity, he notes, describes a four-dimensional continuum of events but does not imply that this continuum exists as a tangible thing.
In physics, spacetime is defined as the continuous set of events throughout space and time, forming a four-dimensional map that records where and when everything happens. An event is an instantaneous occurrence at a specific place and time, while an instant is a three-dimensional collection of simultaneous events. Worldlines trace the paths of objects, like a car's position over time, but these are records of happenings, not existent entities.
Objects, such as people, buildings, and planets, exist and persist through time, occupying places and enduring changes. Events, however, lack empirical evidence of existing like objects; verifying a past event would require a time machine, which does not exist. By recognizing that events happen within an existing world, Janzen argues, time-travel paradoxes dissolve, and debates over time's reality—such as whether its passage is an illusion—gain clarity. Relativity remains a powerful mathematical description of event relations without needing to posit spacetime as existent.
This perspective recovers conceptual clarity in physics and philosophy without altering any predictions, emphasizing that spacetime is an indispensable catalog of happenings rather than a fabric in which they are woven.