 Simon Blackburn developed a more substantial supervenience argument against realism. The details of Blackburn’s various presentations of his argument (1971, 1984, and 1985) are complex and raise difficult interpretive questions; the reconstruction that follows is a rather free interpretation of Blackburn’s (1984, 183–4; for sympathetic discussion, see Mabrito 2005 and Mitchell 2017). The argument starts with two claims: