  This ‘Extensional’ approach – again recalling the terminology of §1.1 – has the definite advantage of allowing change to be perceived in as immediate manner as one might wish for. In subsequent years variants of it will be defended by Mundle (1966), Foster (1979, 1982, 1991), Dainton (2000/2006, 2003, 2008, 2014), Hoerl (2013b), Phillips (2010, 2014b), Rashbrook (2013), Soteriou (2010).   However, although it has its advantages, this model also faces difficulties. How is it possible for contents that are all experienced together, and also as present, seemingly to occur in succession rather than simultaneously? Meinong pointed out a further potentially significant problem. In virtue of what are the successive phases of a temporally extended episode of experiencing unified? What prevents a temporally distributed awareness from also being a fragmented one? This is a difficulty Brentano, Meinong and other Retentional theorists avoid: if the experience of succession is housed in momentary states of consciousness, the problem of securing diachronic unity for temporally distributed experiencings simply does not arise. Allowing consciousness to extend through time may bring advantages, but it is not without costs.