This paper examines Richard Swinburne's definitions of ‘mental property’ and ‘physical property’. After some preliminary tidying up (Section 1), the paper introduces eight putative counter-examples to Swinburne's definitions (Section 2). The paper then considers amendments to Swinburne's account of ‘mental property’ (Section 3) and ‘physical property’ (Section 4) which deal with these counter-examples. Finally, the paper closes with some brief remarks about the metaphysics of properties (Appendix). Along the way, the paper provides various reasons for thinking that Swinburne's definitions are hardly likely to be acceptable to non-theists.