The wide range of conflicting interpretations that exist in regard to Locke's philosophy of mind and body (i.e. dualistic, materialist, idealistic) can be explained by the general failure of commentators to appreciate the full extent of his nominalism. Although his nominalism that focuses on specific natural kinds has been much discussed, his mind-body nominalism remains largely neglected. This neglect, I shall argue, has given rise to the current diversity of interpretations. This paper offers a solution to this interpretative puzzle, and it attributes a view to Locke that I shall describe as nominal symmetry.