 Leibniz rejected materialism on the grounds that it could not, in principle, ever capture the “true unity” of perceptual consciousness, that characteristic of the self which can simultaneously unify a manifoldness of perceptual content. If this is Leibniz’s argument, it is of some historical interest that it bears striking resemblances to contemporary objections to certain materialist theories of mind. Many contemporary philosophers have objected to some versions of materialism on the basis of thought experiments similar to Leibniz’s, experiments designed to show that qualia and consciousness are bound to elude certain materialist conceptions of the mind (cf. Searle 1980; Nagel 1974; McGinn 1989; Jackson 1982). It is also of historical interest that Leibniz coupled his rejection of materialism with a version of naturalism (or what he would have regarded as naturalism - see Jorgensen 2019).