 The literature regards Bayle, not only as an original source for the Enlightenment, but as a conduit of the views and arguments of his immediate predecessors in the seventeenth century. A good example of where Bayle’s role has not been made precise is his discussion of the primary-secondary quality distinction. Bayle is supposed to have conveyed Foucher’s arguments against the distinction to Berkeley and Hume. The contention is that just as Malebranche produced arguments to show that secondary qualities exist only in the mind, so his critic Foucher extended those same arguments to show that primary qualities also exist only in the mind. In fact, however, the arguments that Foucher actually deployed were directed less against Malebranche, whom he took simply to assume the distinction, than against Descartes and especially Rohault. His point was not to undo the distinction, but to show that however it was understood, it was incompatible with Cartesian dualism.