Early 20th century philosopher G.E. Moore's Principia Ethica laid an important foundation for ethics for the remainder of the century and beyond. Moore worked out a metaethical theory and then followed it with his preferred first-order consequentialist theory. It is a genuine tour de force.

Moore developed a famous semantical argument regarding the term 'good' known as the Open Question Argument. He used this argument to develop a metaphysical claim about the nature of the property of goodness. But these issues are a bit ahead of the game. We need to understand what a metaethical theory is, what the basics are for Moore's metaethics, and even what an open question is supposed to be. If you're interested in understanding some of the latter, then please listen to this episode. Two episodes from now, I will discuss Moore's Open Question Argument itself. Thank you for listening!