Stoljar rejects dualism, but defends the use of conceivability arguments. He argues that the appeal of dualism stems from our ignorance about the physical, an ignorance that taints our use of conceivability tests. Stoljar’s central purpose in the book is to show that it is this type of ignorance, and not some other factor, that is principally responsible for the appeal of dualism. The bulk of his arguments target materialists’ competing diagnoses of dualism’s allure. In this study, I sketch Stoljar’s case against rival accounts of how dualist arguments fail. But most of my critical remarks concern his arguments against dualism. For I think the sort of ignorance that Stoljar rightly attributes to us may threaten materialism at least as much as it threatens dualism. Much of this study is devoted to substantiating that claim.