# How could “Law of Reciprocal Proportions” be formulated before “Law of Definite Proportions”?

"Law of Reciprocal Proportions" was formulated in 1792 by Jeremias Richter, and "Law of Definite Proportions" was formulate in 1794 by Joseph Proust. How is this possible? Isn't "Law of Definite Proportions" a prerequisite to "Law of Reciprocal Proportions"?

• The Law of Reciprocal Proportions is less abstract, it states what is directly observed in experiments, the Law of Definite Proportions is a more metaphysical statement as to how compounds are composed. – Conifold Feb 24 at 3:13