Anti-realism

Anti-realism is the philosophical position that certain kinds of entities, properties, or facts do not exist independently of minds, languages, or social practices. Unlike skepticism, which doubts our knowledge of an independent reality, anti-realism denies that the reality in question is independent at all. The position is not a single doctrine but a family of positions spanning mathematics, ethics, science, and aesthetics — united by the claim that the objects of discourse are constructed rather than discovered, shaped by our practices rather than waiting to be found.

The most influential formulation is Michael Dummett's: a theory of meaning is anti-realist if it denies that truth can transcend verification. If a statement's truth conditions outrun any possible evidence — as mathematical platonism claims for statements about infinite sets — then anti-realism holds that such statements are not true-or-false in a robust sense. They are assertible or unassertible, proved or unproved, justified or unjustified. Truth becomes an epistemic achievement, not a metaphysical given.

Varieties of Anti-Realism

Mathematical anti-realism holds that mathematical objects are mental constructions, not platonic entities. L.E.J. Brouwer's mathematical intuitionism is the paradigmatic form: a number exists because we can construct it, not because it occupies some abstract realm. The success of proof-theoretic semantics — which defines meaning by inferential role rather than truth conditions — is a technical vindication of this stance. When meaning is given by what we can prove, unprovable truths drop out of the picture.

Scientific anti-realism challenges the view that scientific theories describe a mind-independent reality. Bas van Fraassen's constructive empiricism argues that we should believe only what our theories say about observable phenomena, treating unobservable entities (electrons, quarks, dark matter) as useful fictions rather than real constituents of the world. The theory saves the phenomena; it need not be true to do so.

Moral anti-realism denies that moral facts exist independently of human attitudes and institutions. On this view, murder