This program examines the philosophies of British empiricists John Locke and George Berkeley. World-renowned author and professor Bryan Magee and philosopher Michael Ayers of Oxford interpret Locke’s skeptical theory that all knowledge is sensory and speculative, and that the true nature of the world can never be known, as an attack on Descartes’s theory of innate ideas. Conversely, Berkeley insists that we cannot have sensory knowledge of material substances because they exist only in our mind. Even the laws of nature, Berkeley says, are merely the regularities of our own perceptions or ideas. A BBC Production. (46 minutes)