Robert Boyle wrote The Sceptical Chymist, a 1661 book that promoted experimental investigation in chemistry. The work challenged older explanations of matter based on Aristotle’s four elements—earth, air, fire, and water—and the Paracelsian principles of salt, sulfur, and mercury.
Boyle presented his arguments as a dialogue among characters discussing how substances are formed and analyzed. He proposed that matter consisted of tiny particles, or “corpuscles,” whose arrangements and motions produced observable properties. His account was not modern atomic theory, but it encouraged chemists to explain materials through testable physical processes.
The book also questioned the assumption that heating a substance always revealed its fundamental ingredients. Boyle’s insistence on careful experiments, repeatable observations, and clear definitions helped chemistry move away from speculative alchemy toward a more systematic science.
A common mix-up is to credit Antoine Lavoisier, who later established important quantitative laws of chemistry, or John Dalton, who developed a modern atomic theory. Boyle’s achievement came earlier and helped prepare the ground for both.