An Enquiry Concerning the Principles of Morals

An Enquiry Concerning the Principles of Morals is the enquiry subsequent to the Enquiry Concerning Human Understanding. Thus, it is often referred to as "the second Enquiry". It was originally published three years after the first Enquiry. Hume first discusses ethics in A Treatise of Human Nature. He later extracted and expounded upon the ideas he proposed there in his second Enquiry.