In Representational Ideas: From Plato to Patricia Churchland Watson argues that all intelligible theories of representation by ideas are based on likeness between representations and objects. He concludes that 17th century materialist criticisms of having' mental representations in the mind apply to contemporary material representations in the brain, as proposed by neurophilosophers. The argument begins with Plato, with particular stress on Descartes, Malebranche, and Arnauld. He then proceeds with an examination of the picture theory developed by Wittgenstein, Carnap, and Goodman,...