For centuries, Europeans explained fire and rust through phlogiston — an invisible substance thought to escape during burning. It was wrong, yet it marked a shift from mystical alchemy to testable theory. The turning point came with Lavoisier in the 1770s, who proved that combustion was not loss but oxygen combining with matter. From this, modern chemistry was born.
The lesson is clear: progress often passes through “usefully wrong” ideas. Science advances not by dismissing anomalies but by testing them — moving from superstition to discovery.