Concept
Arrow of time
Overview
The arrow of time, also called time's arrow, is the concept positing the "one-way direction" or "asymmetry" of time. It was developed in 1927 by the British astrophysicist Arthur Eddington, and is an unsolved general physics question. This direction, according to Eddington, could be determined by studying the organization of atoms, molecules, and bodies, and might be drawn upon a four-dimensional relativistic map of the world ("a solid block of paper").
The arrow of time paradox was originally recognized in the 1800s for gases (and other substances) as a discrepancy between microscopic and macroscopic description of thermodynamics / statistical physics. At the microscopic level physical processes are believed to be either entirely or mostly time-symmetric: if the direction of time were to reverse, the theoretical statements that describe them would remain true. Yet at the macroscopic level it often appears that this is not the case: there is an obvious direction (or flow) of time.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
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The idea of time, being derived from the succession of our perceptions of every kind, ideas as well as impressions, and impressions of reflection as well as of sensation, will afford us an instance of an abstract idea, which comprehends a still greater variety than that of space, and yet is represented in the fancy by some particular individual idea of a determined quantity and quality. As 'tis from the disposition…
David Hume, Philosophical Works, v. 1
The author is tied to Arrow of time in the knowledge graph.
If the actuating force cease after this operation, matter must remain for ever in disorder, and continue an immense chaos, without any proportion or activity. But suppose that the actuating force, whatever it be, still continues in matter, this first position will immediately give place to a second, which will likewise in all probability be as disorderly as the first, and so…
David Hume, Philosophical Works, v. 2
The author is tied to Arrow of time in the knowledge graph.
They held that locomotion consisted in the translation of each atom of a body from one point to the next one; accordingly the velocity of one body in motion cannot be greater than that of another body. When, nevertheless, two bodies are observed to move during the same time through different spaces, the cause of this difference is not attributed by them to the fact that the body which has moved through a larger…
Moses Maimonides, The guide for the perplexed
States what Arrow of time is.
Philosophers who discussed Arrow of time
Related ideas
- Second law of thermodynamics
- Hindi
- Future
- Quantum decoherence
- Molecule
- Arthur Eddington
- Physics
- Paradox
- Scientific law
- Statistical mechanics
- Thermodynamics
- Time
- Memory
- Volition
- Causality
- Big Bang
- Reason
- Consciousness
- Chinese language
- Wave function collapse
- David Hume
- English language
- Atom
- Evolution
Place in the tradition
Part of Philosophy of physics.