Richard Eldridge

BY THE middle of the nineteenth century, serious difficulties in carrying out the Cartesian project of explaining through attention to our ideas how we may know things as they really are had become evident. A satisfactory account of the connection between occurrences of ideas in us and the properties of things apart from our ideas of them, an account promised by Descartes in the Meditations, had not been forthcoming. Descartes' claim that God's omnipotence guarantees that the members of some recognizable class of our ideas, the class of clear and distinct perceptions, represent things as they really are became clearly unsatisfactory as part of a realist theory of knowledge as soon as Hume and Kant had shown the unsoundness of Descartes' proofs of the existence of God. Whether or not God's omnipotence guarantees that we can know things as they are, it had become evident that we lack adequate grounds for claiming to know that this is the case. Consequently, there developed by the middle of the nineteenth century a consensus that we lacked a satisfactory account of how our ideas enable us to know things.