blockuniverse

Block universe, also known as eternalism, is a view in the philosophy of time and in some interpretations of physics that treats spacetime as a four-dimensional block in which events across time exist with equal ontological status. According to this view, the past, present, and future are all real, and the sense of time flowing or changing is a feature of consciousness rather than a property of the world. Time is considered another dimension, similar to space, in which events are located.

Origin and development of the idea are closely tied to the physics of relativity. The mathematical framework of Minkowski spacetime and the relativity of simultaneity suggest there is no unique, objective present moment across all observers. Proponents argue that this supports the idea that all moments in time are equally real, even if observers disagree on which moment is “now.”

Variants and implications include contrasts with presentism, which holds that only present events exist, and with the growing block theory, which posits that the past and present exist while the future does not. In the block universe, the entire history of the universe is laid out in the four-dimensional fabric of spacetime, with determinism sometimes inferred but not universally required by the view.

Critics challenge how the block universe accounts for the felt experience of temporal passage, change, and human agency. Defenders contend that it coheres with empirical physics and reframes becoming as a subjective aspect of experience rather than an ontological feature of reality. See also eternalism, presentism, growing block, and Minkowski spacetime.