This chapter traces the development of the problem of consciousness in Western philosophy from the time of the ancient Greeks to the middle of the 20th century. The core problem of consciousness focuses on the nature of subjectivity. The chapter focuses on what has become the central issue in consciousness studies, which is the problem of integrating subjectivity into the scientific view of the world. The mainstream view has not long been mainstream, for the problem of consciousness cannot strike one at all until a fairly advanced scientific understanding of the world permits development of the materialism presupposed by the mainstream view. It was the scientific revolution of the 16th and 17th centuries that forced the problem of the Christian dogma into prominence. In philosophy, the 1950s saw the beginning of a self-conscious effort to understand the mind and, eventually, consciousness as physical through and through in essentially scientific terms.