Views of time

Thinkers

Each thinker has a page of their own: the view, the argument behind it, and where it parts company with Deutsch.

Each entry is marked by its answer to one question: does time flow? Compare all views side by side → · The felt present: time in the mind →

The Greeks

• Heraclitusc. 535–475 BCFlows

  Everything flows. Change is the deepest fact about the world.

• Parmenidesc. 515 – after 450 BCDoes not flow

  What is, simply is. Change and passage are illusions of the senses: an ancient ancestor of the block universe.

• Zeno of Eleab. c. 490 BCQualified

  The paradoxes of the arrow and Achilles, built to show that motion through time is incoherent.

• Platoc. 428–348 BCFlows

  Time as the moving image of eternity, created along with the heavens.

• Aristotle384–322 BCFlows

  Time as the number of change with respect to before and after. No change, no time.

Late antiquity and early modern

• Augustine354–430Flows

  What then is time? Past and future exist only in the mind, as memory and expectation.

• Isaac Newton1642–1727Flows

  Absolute, true and mathematical time flows equably, without relation to anything external.

• Gottfried Wilhelm Leibniz1646–1716Qualified

  Time is the order of successions, not a container. A world created a year earlier would be no different.

• Immanuel Kant1724–1804Qualified

  Time is the form of inner sense. Asking whether the world began in time sets reason against itself.

Modern and contemporary

• Henri Bergson1859–1941Flows

  Real time is lived duration, not a line of instants. Debated Einstein in Paris in 1922.

• J. M. E. McTaggart1866–1925Qualified

  Split time into the A-series (past, present, future) and B-series (earlier, later), then argued time is unreal.

• Albert Einstein1879–1955Does not flow

  Simultaneity is relative, so there is no universal now. Past, present and future are a persistent illusion.

• Arthur Prior1914–1969Flows

  Founder of tense logic and a defender of the reality of the present.

• D. H. Mellor1938–2020Does not flow

  A tenseless B-theorist: tensed facts are not part of reality, though tensed beliefs are indispensable.

• Robin Le PoidevinDoes not flow

  The temporal prison: if only the present can act, and the present is an instant, how can a conscious mind ever act?

• Julian Barbourb. 1937Does not flow

  Time does not exist; there are only "Nows", configurations of the universe. The closest ally to Deutsch's snapshots.

• Huw Priceb. 1953Does not flow

  The view from nowhen: the arrow of time is a fact about us and boundary conditions, not about time itself.

• Lee Smolinb. 1955Flows

  Time is real and fundamental, and even the laws of physics evolve. A direct challenge to Deutsch.

• Tim Maudlinb. 1958Flows

  Time passes, and its passage is an intrinsic direction built into the structure of spacetime.

• Carlo Rovellib. 1956Qualified

  Relational time and the thermal time hypothesis: the flow we feel comes from our blurred view of the world.

• Sean Carrollb. 1966Does not flow

  The arrow of time comes from the low-entropy Big Bang, set within an Everettian multiverse.

• Jenann IsmaelDoes not flow

  The experience of passage explained from inside a timeless block, through how embedded agents gather information.

• Craig CallenderDoes not flow

  What makes time special: why physics treats time differently from space, and what that does to the manifest image.