Mandelbrot, Financial Markets and the Origins of "Econophysics"

TL;DR

This paper explores the origins of econophysics through Mandelbrot's methodological approach, emphasizing empirical data features and endogenous dynamics in financial markets, and advocates for using concepts from statistical physics to understand market phenomena.

Contribution

It reinterprets Mandelbrot's role in econophysics, highlighting a methodological shift towards models that embrace data features and endogenous interactions rather than external narratives.

Findings

Scaling, intermittency, and extremes are fundamental to financial fluctuations.

Endogenous dynamics and feedback loops contribute to market fragility.

Statistical physics concepts offer generic mechanisms consistent with empirical data.

Abstract

This text revisits the origins of econophysics through the figure of Beno\^it Mandelbrot, not as the father of fractals, but as the instigator of a distinctive scientific posture. The guiding thread is methodological: accept the stubborn features of the data and use models as instruments for intuition rather than as axiomatic certificates of truth. In this perspective, scaling, intermittency and extremes are not peripheral imperfections around a well-behaved equilibrium; they are the very texture of economic and financial fluctuations. This naturally shifts attention from exogenous narratives to endogenous dynamics: interactions, feedback loops, and collective amplification mechanisms that can make systems intrinsically {\it fragile}. We argue that the importation of concepts from statistical physics -- criticality, disorder, emergence, multiplicative cascades -- should be read not as an artificial transposition but as a candid attempt to look for generic mechanisms compatible with empirical regularities observed across scales, from markets to macroeconomic aggregates.