This is a comprehensive reference source on 18th-century authors writing in the English language about philosophical ideas and issues. It features authors taken from 1689 through to the mid-19th century, the period beginning with John Locke and ending with Dugald Stewart. The word philosophical is used in a wide, 18th-century sense. Therefore, the Dictionary includes epistemology, ethics, aesthetics, education, politics, rhetoric, science, medicine, biology, geology, chemistry and theology.