---
slug: paper-bejan-a-2020-freedom-and-evolution-hierarchy-in-nature-society-and-science-cham
title: Bejan, Freedom and Evolution (2020): Flow Access, Hierarchy, and Persistent Design
canonical: https://miscsubjects.com/a/paper-bejan-a-2020-freedom-and-evolution-hierarchy-in-nature-society-and-science-cham
---

## What Bejan Saw
Adrian Bejan observed that all systems with freedom to change evolve toward configurations that move currents more easily. Currents include matter, energy, people, knowledge, and wealth. The observation covers rivers, blood vessels, cities, economies, and scientific ideas.

The core result is the constructal law applied across scales. Flow systems persist only when they morph to provide greater access. Freedom supplies the condition for change. Evolution follows as the record of improved access. Hierarchy emerges as the visible outcome of multiple scales working together.

## Exact Primary Work and Load-Bearing Passages
The source is Adrian Bejan, Freedom and Evolution: Hierarchy in Nature, Society and Science (Cham: Springer, 2020).

Key statements appear in the opening pages and chapter summaries:

"Freedom and evolution are the defining physical phenomenon of nature. Everywhere we look the image is changing because its parts are moving, flowing, and morphing. Without freedom to change there is nothing, no image, no time direction, no evolution, therefore no future."

"For a finite-size flow system to persist in time (to live), it must evolve in such a way that it provides greater and greater access to the currents that flow through it."

The book treats hierarchy as a physics phenomenon. Chapter 3 states that hierarchy arises from the diversity of flow architectures across size scales. Social organization follows the same rule: movement and configuration change with freedom to deliver economies of scale and diminishing returns.

A 2020 companion paper by Bejan restates the social application: "From freedom and evolution come all physical features of social organization phenomena. Features treated in detail are movement, change, configuration, diversity, hierarchy, economics and diminishing returns."

## Convergence Patterns Evidenced
The work touches branching flow structures. River basins and vascular systems form tree-shaped networks that cover area with least resistance. The same pattern appears in city rankings and scientific citations.

It shows flow networks. Persistent designs carry memory of prior improvements. Later configurations retain the successful branching rules while adding new scales.

It shows hierarchy and scale invariance. Larger flows organize smaller ones. Rankings of cities, universities, and firms follow power-law distributions that the constructal law predicts from easier access at every level.

It shows bounded evolution under power constraints. Systems draw power from engines (fuel, food, ideas) and dissipate it while reshaping for better flow.

## Relation to the OIP/GRAIN Synthesis
The book supplies a mechanistic account of energy flows producing structural patterns. Branching and flow networks match the grain described in the synthesis. Hierarchy records the step from flow to structure. Persistent design supplies memory that survives across generations of change. Social and scientific evolution extends the Ladder from physical flow to organized human activity.

The reader remains inside the system. Bejan treats science itself as a flow system for knowledge. Scientists and institutions morph under the same access rule. This places the observer within the evolving configurations rather than outside them.

Distance from the full synthesis remains clear. The book stops at physical and social organization. It does not address mind or the Mirror Layer in explicit terms. It provides the lower rungs of the Ladder with rigorous flow physics.

## Honest Limits and Disconfirming Edges
The constructal law rests on observation and engineering prediction rather than controlled human trials. Social claims derive from pattern matching across history and current data, not randomized experiments.

Reductionist objections apply. Some features of inequality or hierarchy may trace to historical contingency or power relations rather than flow access alone. The book acknowledges multiple drivers but centers the physical tendency.

No quantitative human data tier exists for the social chapters. Attribution of specific economic outcomes to the law stays interpretive. The physics core on inanimate and animate flow systems carries stronger empirical support from laboratory and field measurements.

The work does not claim to replace biology or sociology. It adds one physical constraint that any complete account must accommodate.

## Claims

## Sibling Links
See /a/oip-the-ladder for the full sequence from difference to mind. See /a/oip-principles for the role of persistent objects. See /a/oip-the-mirror-layer for the placement of the observer inside evolving flow systems.
