  The Overlap Model looks to be the most promising variant of the Extensional approach. Like other Extensional accounts, it allows change and succession to be directly experienced in a clear and unambiguous manner, and so fully satisfies the requirements of realism. Also, by virtue of the fact that each successive phase of an Extensional specious present contains ordinary first-order experiences, the requirements of the Immediacy Thesis are also met: change and succession can be experienced with maximal (phenomenal) vividness. Further, and distinctively, the Overlap Model secures both Modest and Strong Continuity: not only is a (typical) stream of consciousness a gap-free stretch of experience, but each of its successive brief phases is experientially connected to its immediate neighbours. Kelly (2005: 231) points out that for the Extensional approach to be viable it must be able to explain how we manage to perceive continuous changes which last longer than the specious present, which in turn requires an explanation of how it is possible for specious presents to be strung together; he also suggests no such explanation is available. The Overlap approach provides just such an explanation.