---
slug: oip-node-c02-least-action-variational-principles
title: Node C02: Least Action / Variational Principles
canonical: https://miscsubjects.com/a/oip-node-c02-least-action-variational-principles
---

# Node C02: Least Action / Variational Principles

C02 — Least Action / Variational Principles
{
  "id": "C02",
  "claim": "Nature extremizes a quantity (action, entropy, energy) across all fundamental domains; the actual path is the stationary path.",
  "domain": ["classical mechanics", "quantum mechanics", "optics", "thermodynamics", "general relativity", "economics", "machine_learning"],
  "pattern": ["extremization", "variational_principle", "economy_of_nature"],
  "mechanism": "The Euler-Lagrange equations derive from demanding that the integral of the Lagrangian (kinetic minus potential energy) be stationary. Feynman showed this emerges from constructive interference of amplitudes in the path integral formulation.",
  "scale": "quantum → cosmic",
  "claim_tier": "T0/T1",
  "sources": [
    "Fermat, P. de (1662). Principle of Least Time in optics (published posthumously).",
    "Maupertuis, P.L. (1744). 'Accord de plusieurs lois naturelles...' — principle of least action.",
    "Lagrange, J.L. (1788). Mecanique Analytique — generalized variational mechanics.",
    "Hamilton, W.R. (1833). 'On a General Method in Dynamics.'",
    "Feynman, R.P. (1948). 'Space-Time Approach to Non-Relativistic Quantum Mechanics.' Rev. Mod. Phys., 20, 367-387."
  ],
  "dual": "None — this IS the economy principle. The dual would be a universe with no extremization (no consistent physics).",
  "falsifier": "Discovery of a fundamental physical law not expressible as an extremum principle — i.e., a dynamics with no Lagrangian or action formulation.",
  "rival_frame": "Nature does not 'choose.' The path integral formulation is a mathematical convenience for calculation, not a physical mechanism. The universe computes one path locally; the global extremization is a retrospective overlay by theorists.",
  "independence_check": "EXTREMELY HIGH. Fermat (optics, 17th c. France) worked from Snell's law of refraction. Lagrange (mechanics, 18th c. Turin/Paris) worked from d'Alembert's principle. Feynman (quantum mechanics, 20th c. Princeton/MIT) worked from Dirac's q-numbers. Three fields, three centuries, three unrelated starting points, same mathematical structure.",
  "pattern_type": "mathematical",
  "maps_to_axiom": ["A2", "A9"]
}

---

## Corpus map
- Same node, other planes: [Encyclopedia C02](/a/convergence-encyclopedia-c02) · [Inventory invariant](/a/oip-invariant-2-32-least-action-variational-principles)
- Edges touching C02: [convergence edge 2](/a/oip-convergence-edge-2) · [disconfirming edge 3](/a/oip-disconfirming-edge-3)
- Catalogue hub: [Public Article](/a/oip-convergence-public-article) · [Schema](/a/oip-convergence-schema)
