  No less important is the Retentional theorists’ solution to the problem of diachronic phenomenal unity. All forms of the Extensional approach stipulate that our immediate awareness is capable of routinely bridging a temporal interval. This could be viewed as admitting an unusual – and arguably undesirable – form of action-at-a-distance. Retentional models are free of this heavy commitment: the only mode of phenomenal unity such models require is the sort which connects contents that are both momentary and simultaneous. By virtue of their conformity with PSA, Retentional models offer an appealing reduction of diachronic unity to synchronic unity. Again, this option is not available to Extensional theorists, who are obliged to recognize two forms of phenomenal unity rather than just one. Further, as we saw in §2.5 and §5.5, there are those – e.g., Meinong – who believe that incurable problems arise if we suppose phenomenal unity can extend over time. Though we as also saw in §5.5, the Extensional theorists can, with some plausibility, argue that claims along these lines are question-begging.