If there is any contribution to moral philosophy which is more likely than any other to become permanently associated with the name of Professor G.E. Moore, it is the identification and refutation, in his Principia Ethica of what he called the naturalistic facility. (A.N. Prior, Logic and the Basis of Ethics, p.1) G.E. Moore is famous in the annals of moral philosophy for his coinage of the term naturalistic fallacy as well as his twin theses of the indefinability and intuitiveness of good. The present study examines Moores these and attempts to assess his influence on contemporary moral philosophers.