The terms ‘compatibilism’ and ‘incompatibilism’ were introduced in the mid-20th century to name conflicting views about the logical relationship between the thesis of determinism and the thesis that someone has free will. These technical terms were originally introduced within a specific research paradigm, the classical analytic paradigm. This paradigm is now in its final stages of degeration and few free-will theorists still work within it (i.e. using its methods, granting its substantive background assumptions, etc.). This chapter discusses how the ambiguity of the terms ‘incompatibilism’ and ‘compatibilism’ took root and why it matters to the contempory debate. I explain why the ambiguity of these anachronistic terms, though relatively i...