Dreams may be a side-effect of the brain's housekeeping but there must be some reason why a system so good at shielding consciousness from other necessary and ancillary labours should insist that it participate in this one. Whatever the manifest content of dreams they generally force you to feel things you were resisting feeling, things at the edge of range of acceptability for the waking synthesis. Simple defences against insecurity which work pretty well in the waking state lose their effectiveness in the dream state because of a small augmentation in the transparency of consciousness. The medium becomes too thin and suddenly it is impossible to build anything enduring enough to sustain an entire episode for a coherent protagonist. Instead the episode comes to be about the defence itself, or rather about a process, in some general sense, of which the defence is one instance. The plot may become absurdly twisted but the succession of moods, the ways in which actions incur certain feelings, is dictated from the heart of the proceedings in which the same mind plays prosecutor and defence. Each dream is a case, and hence that vaguely forensic atmosphere that pervades them. In the waking state a change of mood may be linked to the sudden activation of an accuser, but part of the quotidian defence is to see this encounter as an isolated event; in a dream the accuser is backed by an entire, but mostly invisible, system, one which has something shady and dishonest about it since it is in fact no other than ourself that lies behind it. It is as if in order for the brain to carry out its maintenance it must  turn the lights up even brighter, must increase the level of consciousness, and so in order to counter all the confusion this could cause it paralyses or depresses some other functions, such as memory - access to old memories as well as formation of new ones - and as much rational interconnectedness as possible.