Principia Ethicais a foundational text in the analytic tradition of ethical theory andG. E. Moore’smost influential book. In it, he defines the subject of ethics as the general enquiry into the question “what is good?” and famously contends that the predicate “good” is indefinable. Moore claims that whatever definition is offered of the predicate, “it may be always asked, with significance, of the complex so defined, whether it is itself...
