How did Joseph Black’s views on combustion differ from Antoine-Laurent Lavoisier’s oxygen theory?

Joseph Black’s views on combustion were initially rooted in the phlogiston theory, which dominated 18th-century chemical thought. This theory posited that combustible materials contain a weightless, invisible substance called phlogiston, which is released into the air during burning, respiration, and calcination.123

In contrast, Antoine-Laurent Lavoisier developed an oxygen theory of combustion starting in 1775. Lavoisier’s work demonstrated that combustion is not the release of a substance but rather a process of oxygenation, where a material combines with oxygen from the atmosphere.231

While Black was a pioneer in pneumatic chemistry—notably discovering "fixed air" (carbon dioxide)—he was initially reluctant to abandon the phlogiston theory in favor of Lavoisier’s oxygen-based explanation. Despite pressure from his students to accept the new theory, Black did not fully concede to Lavoisier’s views until 1790, when he finally entered into correspondence with the French chemist and acknowledged the validity of the oxygen theory.412