The Anti-realist Argument for Underdetermination

Typically, anti-realists argue for the underdetermination of theory by the data (UD) on the basis of the claim that each theory has empirically equivalent rivals (EE). Leplin has recently sought to show that, whatever the truth-value of this latter claim, it cannot play any positive role in an argument for underdetermination. I argue that Leplin's attempt fails.