Gas in a box or nuclear explosion?

Gas in a box or nuclear explosion?

This post is about mindset, culture, implicit assumptions. The big assumption in neoclassical economics is ergodicity, or equilibrium, or stationarity, or stability — basically the idea that nothing ever changes fundamentally. Things may fluctuate but they always return to some state of normality. Naively, that doesn’t fit with the idea of a growing economy, innovation, and change. So something’s up. I’ll explore what that is by replacing the mental image of stability with something that doesn’t return to normality: a nuclear explosion.

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Reproducibility and weak ergodicity breaking

Reproducibility and weak ergodicity breaking

The term “weak ergodicity breaking” helps categorize things by their ergodic properties:

  1. ergodic
  2. strongly non-ergodic
  3. weakly non-ergodic

This list is chronological, in that there used to be an implicit belief that everything was ergodic (from 1654), then the realization that some things are strongly non-ergodic (1850s — 1870s), and then the discovery that things can be a lot more subtle (with Jean-Philippe Bouchaud coining the term “weak ergodicity breaking” in 1992).

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