 If qualia have no physical effects, then nothing will enable anyone to establish for certain that anyone else actually has qualia. Philosophers who believe they have a solid response to skepticism about other minds may therefore conclude that this consequence of the zombie idea is enough to condemn it. Others, however, may regard the skeptical consequence as ‘a confirmation’, on the ground that we really are ignorant of others’ minds (Campbell 1970, 120). Of course not all responses to other minds skepticism imply that zombies are inconceivable.