 Thomas Reid, known for his theory of perception and an epistemic theory he calls “common sense”, urges a version of the distinction of qualities in two of his main philosophical works: An Inquiry into the Human Mind on the Principles of Common Sense (1764) and Essays on the Intellectual Powers of Man (1785). Both use an empirical method to investigate basic faculties of the human mind such as perception, conception, and judgment. Qualities of bodies are identified as the objects of perception. Among them, Reid finds the foundation of a division aligned with the standard lists of PQs and SQs presented as a difference in how we know them. Some scholars maintain his doctrine of P/SQs is entirely epistemic (Lehrer 1978; McKitrick 2002), but others contend it depends on a metaphysical distinction (Van Cleve 2015: 110–12).