 While those antagonistic to overflow have argued that it is not empirically testable (M.A. Cohen &amp; Dennett 2011), gatekeeping might be equally untestable. After all, to test the necessity of attention for consciousness, we must eliminate attention to a target while gathering evidence for the absence of consciousness. Yet if gathering evidence for consciousness requires attention, then in fulfilling the conditions for testing the necessity of attention, we undercut the access needed to substantiate the absence of consciousness (Wu 2017; for a monograph length discussion of attention and consciousness, see Montemayor &amp; Haladjian 2015). How then can we gather the required evidence to assess competing theories?