CONCEPT
Phlogiston Theory
The 18th-century chemical framework that organized combustion through the release of a substance — Bachelard's canonical example of an epistemological obstacle invisible to its practitioners.
Phlogiston theory, developed by Georg Ernst Stahl in the late 17th century and dominant throughout the 18th, organized the entire field of chemistry around the assumption that combustible materials contained a substance called phlogiston, released into the air during combustion. A burning log released phlogiston; rust was the slow release of phlogiston from metal; a candle in a sealed jar guttered when the surrounding air had been saturated with phlogiston and could absorb no more. The theory was elegant, consistent, and explained every observable phenomenon of combustion with economy. For nearly a century, it organized laboratories, textbooks, and experimental interpretation. Lavoisier destroyed it in less than a decade by demonstrating that combustion involves not release but combination with oxygen — making phlogiston's entire conceptual universe uninhabitable.
In The You On AI Field Guide
Bachelard returned to phlogiston repeatedly across his philosophy of science because it represents the cleanest available historical example of his theoretical claims. The theory was not wrong in a simple sense — it explained available