In this paper I shall critically discuss G. E. Moore's Defence of Common Sense with the purpose of showing that Moore's idea of defending common sense was entirely mistaken. This mistake is based, as I shall try to show, firstly on a mistaken notion about the nature of common sense and, secondly, on a mistaken notion about the relation between common sense beliefs and philosophy. Nothing that I say in this paper regarding the value and the validity of Moore's Defence of Common Sense should be taken as reflecting my opinion about the other aspects of Moore's philosophy.