English

Why do we remember the past and not the future? The 'time oriented coarse graining' hypothesis

High Energy Physics - Theory 2014-07-17 v2 Statistical Mechanics General Relativity and Quantum Cosmology

Abstract

Phenomenological arrows of time can be traced to a past low-entropy state. Does this imply the universe was in an improbable state in the past? I suggest a different possibility: past low-entropy depends on the coarse-graining implicit in our definition of entropy. This, in turn depends on our physical coupling to the rest of the world. I conjecture that anyany generic motion of a sufficiently rich system satisfies the second law of thermodynamics, in either direction of time, for somesome choice of macroscopic observables. The low entropy of the past could then be due to the way we couple to the universe (a way needed for us doing what we do), hence to our natural macroscopic variables, rather than to a strange past microstate of the world at large.

Keywords

Cite

@article{arxiv.1407.3384,
  title  = {Why do we remember the past and not the future? The 'time oriented coarse graining' hypothesis},
  author = {Carlo Rovelli},
  journal= {arXiv preprint arXiv:1407.3384},
  year   = {2014}
}

Comments

5 pages. Few equations. An idea

R2 v1 2026-06-22T05:02:39.362Z