SOURCE: "Moore's 'The Refutation of Idealism'," in The Philosophy of G. E. Moore, edited by Paul Arthur Schlipp, Northwestern University, 1942, pp. 225-52.

In the following essay, Ducasse challenges Moore's belief that esse (to be) is not necessarily percipi (to be perceived).

Professor Moore's "The Refutation of Idealism," published in 1903, is still one of the most famous articles written in philosophy since the turn of the century. Its acute and searching criticism of the proposition that esse is percipi has been widely held to have finally proved its falsity and thus to have robbed of their basis the idealistic philosophies which in one way or another had been built upon it. It is true that in the preface to his Philosophical Studies—in which the article was reprinted in 1922—Professor Moore writes that "this paper now appears to me to be very confused, as well as to embody a...