UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Path integrals, particular kinds, and strange things

Friston, K; Da Costa, L; Sakthivadivel, DAR; Heins, C; Pavliotis, GA; Ramstead, M; Parr, T; (2023) Path integrals, particular kinds, and strange things. Physics of Life Reviews , 47 pp. 35-62. 10.1016/j.plrev.2023.08.016. Green open access

[thumbnail of 1-s2.0-S1571064523001094-main.pdf]
Preview
Text
1-s2.0-S1571064523001094-main.pdf - Published Version

Download (1MB) | Preview

Abstract

This paper describes a path integral formulation of the free energy principle. The ensuing account expresses the paths or trajectories that a particle takes as it evolves over time. The main results are a method or principle of least action that can be used to emulate the behaviour of particles in open exchange with their external milieu. Particles are defined by a particular partition, in which internal states are individuated from external states by active and sensory blanket states. The variational principle at hand allows one to interpret internal dynamics—of certain kinds of particles—as inferring external states that are hidden behind blanket states. We consider different kinds of particles, and to what extent they can be imbued with an elementary form of inference or sentience. Specifically, we consider the distinction between dissipative and conservative particles, inert and active particles and, finally, ordinary and strange particles. Strange particles can be described as inferring their own actions, endowing them with apparent autonomy or agency. In short—of the kinds of particles afforded by a particular partition—strange kinds may be apt for describing sentient behaviour.

Type: Article
Title: Path integrals, particular kinds, and strange things
Location: Netherlands
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.plrev.2023.08.016
Publisher version: https://doi.org/10.1016/j.plrev.2023.08.016
Language: English
Additional information: © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
Keywords: Self-organisation; Variational inference; Bayesian; Markov blanket; Active matter; Path integral
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience
URI: https://discovery.ucl.ac.uk/id/eprint/10176959
Downloads since deposit
33Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item