 Be that as it may, Warfield (1998) and Sawyer (1998) are often interpreted as embracing the reductio qua anti-skeptical argument. But the fact is that Warfield is mostly addressing Putnam’s (1981) argument. (Warfield mentions the reductio in passing, but he endorses Brueckner’s 1992 compatibilism from section  2.1,  instead of a transcendentalist reply.)