The period from 1500 to 1750 is commonly referred to as the scientific revolution. Science and philosophy were one and the same; together with theology, they merged into Orthodox scholasticism. John Locke adopted the observational/experimental methods of the great contemporary scientists as his ideal model for how the human mind operates best. In the In Defence of Empirical Psychology, Donald Broadbent, an ardent Behaviourist, equated empirical Psychology with Behaviourism. Descartes' dualism represents one attempt to describe the relationship between mind or consciousness, the essence of mind and body, often referred to as the mind-body or mind-brain problem. Thomas Kuhn, along with other philosophers of science claims that empirical observations are theory-laden: theory literally determines how the people see the world. Many Feminist Psychologists argue that the major 'sin' of mainstream Psychology is its denial of values, resulting in its sexism, specifically, and its masculinist bias.