  Confining the experience of change to momentary episodes of experiencing may have its advantages, but it also makes for difficulties of a distinctive sort. It might be objected that it is simply impossible for the temporal properties of experiences and their contents to diverge so dramatically: how could the latter be temporally extended when the former are not? In reply, the Retentional theorist can point out that it is widely accepted that the properties of representational vehicles, and the contents carried by these vehicles, commonly diverge – although in this instance there are certain significant complications (for further discussion of this issue see §7.1). Also pertinent here is our current level of ignorance concerning the relationship between the experiential and the physical. Given that we are sure of so little in this domain, do we have any real grounds for supposing that it is impossible for momentary (or very brief) brain-states to generate experiences which possess temporal depth on the subjective or phenomenal level?