An Argument for Metaphysical Realism

This paper presents an argument for metaphysical realism, understood as the claim that the world has structure that would exist even if our cognitive activities never did. The argument is based on the existence of a structured world at a time when it was still possible that we would never evolve. But the interpretation of its premises introduces subtleties: whether, for example, these premises are to be understood as assertions about the world or about our evidence, internally or externally, via assertibility conditions or truth conditions – and what sorts of beings are included in the `we' upon whose cognitions the antirealist supposes the structure of the world to depend. I argue that antirealism can provide no defensible, fully articulated interpretation of the premises that either shows them not to be true or defeats the reasoning.