This thesis evaluates and compares two versions of neutral monism, one developed by William James and the other by Bertrand Russell. Both argued against Cartesianism in favour of a "subjectless given" as the basic stuff which constitutes both mind and matter. My evaluation will demonstrate that James’s and Russell's supposedly neutral entities are not neutral as their exponents claim because they fail to satisfy important criteria set for a theory to be genuinely neutral. There are two fundamental elements within my (...) discussion of the neutral entities. Firstly, I shall demonstrate that although James's initial repudiation of dualistic epistemology of subject and object, knower and known, led him to avoid metaphysical dualism of mental and physical, in Cartesian sense, by committing him to the view that there is one kind of entity called "experience", his final analysis admitted an internal distinction within the supposedly simple neutral entities. I shall call this covert dualism. Accepting James’s radical empiricism as an archetype, Russell’s early commitment to neutral monism led him to assert three distinctive kinds of entities, sensation, image and unperceived, and was therefore not complete as that of James. In order to bring his theory in line with James, Russell, in his mature version, entirely repudiated the dualistic view of perception which, following Moore, he accepted, to reject idealism. Russell declared percept as the neutral entity, which is both mental and material at once. But by re-introducing epistemological dualism, as James did, Russell admitted that a percept is not simple but complete bundle of compresent qualities and relations. 1 shall argue that like James’ his theory also collapses into covert dualism. Secondly, I shall argue that to produce a genuinely explanatory theory of neutral entities James and Russell exploited science to justify their theories. In course of their analysis they produced various arguments which has been considered as circular. An attempt will be made to show that the apparent circularity of their analysis is really part of a sophisticated programme, now known as bootstrapping. The notion of a bootstrap strategy has recently been developed in philosophy of science, and suggests a way in which the same evidence can be used to generate both a general and specific hypothesis. The thesis is divided into eight chapters. Chapters one, two and four are largely exegetical and chronological, and discuss the development of neutral monism especially in James and Russell’s philosophy together with the general characteristics of the theory as distinguished from other theories explaining mind and matter. Chapters three, five and six critically analyse James’s and Russell’s versions respectively to show their theories collapse into covert dualism. In chapter seven we argue that the alleged circularities in their theory are non- viscious and their employment of a bootstrap strategy introduced a profound innovation in epistemology. (shrink)