(1) Assume that the brain has finite capacity for memory. (2) Therefore with the infinity of stimulus around us, by (1) there isn't enough memory for it all to be stored in full fidelity. (3) "Live algorithms" -- those that operate while a system is in motion -- are incredibly difficult and finicky when compared to "offline algorithms." (4) By (2) and (3), figure that a human's sleep-state is a natural opportunity for "compressing" memory while many perceptual inputs are attenuated. (5) Due to (4), postulate that sleep is the time when "short term" memory is incorporated into "long term," and extraneous memories are selected and discarded. (6) "Loading" memories from dusty neural recesses to process them as in (5) must require "staging" or "working" space. Perhaps regions of the brain more usually utilized for perception and immediate recall are used to juggle memories around. (7) Then we can understand a "dream" as perception of such a structural "recompression" process (5, 6), noting anecdotally a tendancy for dreams to involve both very recent, as well as oddly distant memories. And this does not deny "meaning" to dreams -- they are not random, but in fact would reveal tremendous associative structure, concerned as they are with the "indexing" and organization of the brain. (8) But a paranoid consequence of (7) is that once an old memory renders through a dream, it may be just shuffling around, recompressing, or else on its way forever out, deleted and discarded. The "dream" --a second-order perception of the memory reprocessing algorithm, can be a "last chance" to keep memories.