Substance Dualism and Disembodied Existence

In a number of places, Richard Swinburne has defended the logical possibility of perception without a body; and has inferred from this logical possibility that substance dualism is true. I challenge his defence of disembodied perception by arguing that a disembodied perceiver would not be able to distinguish between perceptions and hallucinations. I then claim that even if disembodied perception were possible, this could not be used to support substance dualism: such an inference would be either invalid or question-begging