According to the Phenomenal Unity Thesis (“PUT”) – most prominently defended by Tim Bayne and David Chalmers – necessarily, any set of phenomenal states of a subject at a time is phenomenally unified. The standard formulation of this thesis is unacceptably vague because it does not specify what it is to be a subject. In this paper, I first consider possible meanings for ‘subject’ as used in PUT and argue that every plausible candidate definition renders the thesis trivially true. I (...) consider and reject Tim Bayne’s proposal that ‘subject’ means ‘human being’. Then I argue, contra Bayne and Chalmers, that PUT is not incompatible with any major theory of consciousness, and contra Michael Tye, that split-brain patients do not provide evidence against PUT. I close by considering some nontrivial alternatives to PUT. (shrink)