  A further, and no less deep, motivation for the Retentional view is connected with the common sense considerations mentioned above: tacit assumptions, of a broadly metaphysical character, concerning the structure or nature of time itself are very relevant in this context. There may well be no single conception of time which perfectly fits all our common sense assumptions about it, but Presentism – the doctrine, favoured by Augustine, that neither the past nor the future exist, and hence that only the present is real – fits them better than most. If the momentary present is all that is real, there is no obvious option but to locate our experience of change and persistence in the momentary present. (The relationship between different conceptions of temporal consciousness and different ways of thinking about time per se is the topic of §7.2 below.)