To process repressed emotions (wishes, in Freud's speech) and other mental content which was suppressed and stored in unconscious. To order, classify and, generally, to pigeonhole conscious experiences of day or days preceding dreaming ("day residues"). A partial overlap with former function is inevitable: some sensory input is immediately relegated to darker and dimmer kingdoms of subconscious and unconscious without being consciously processed at all. To "stay in touch" with outside world. External sensory input is interpreted by dream and represented in its unique language of symbols and disjunction. Research has shown this to be a rare event, independent of timing of stimuli: during sleep or immediately prior to it. Still, when it does happen, it seems that even when interpretation is dead wrong – substantial information is preserved. A collapsing bedpost (as in Maury's famous dream) will become a French guillotine, for instance. The message conserved: there is physical danger to neck and head. All three functions are part of a much larger one:

The continuous adjustment of model one has of one's self and of one's place in world – to incessant stream of sensory (external) input and of mental (internal) input. This "model modification" is carried out through an intricate, symbol laden, dialogue between dreamer and himself. It probably also has therapeutic side benefits. It would be an over-simplification to say that dream carries messages (even if we were to limit it to correspondence with one's self). The dream does not seem to be in a position of privileged knowledge. The dream functions more like a good friend would: listening, advising, sharing experiences, providing access to remote territories of mind, putting events in perspective and in proportion and provoking. It, thus, induces relaxation and acceptance and a better functioning of "client". It does so, mostly, by analysing discrepancies and incompatibilities. No wonder that it is mostly associated with bad emotions (anger, hurt, fear). This also happens in course of successful psychotherapy. Defences are gradually dismantled and a new, more functional, view of world is established. This is a painful and frightening process. This function of dream is more in line with Jung's view of dreams as "compensatory". The previous three functions are "complementary" and, therefore, Freudian.

It would seem that we are all constantly engaged in maintenance, in preserving that which exists and inventing new strategies for coping. We are all in constant psychotherapy, administered by ourselves, day and night. Dreaming is just awareness of this on-going process and its symbolic content. We are more susceptible, vulnerable, and open to dialogue while we sleep. The dissonance between how we regard ourselves, and what we really are and between our model of world and reality – this dissonance is so enormous that it calls for a (continuous) routine of evaluation, mending and re-invention. Otherwise, whole edifice might crumble. The delicate balance between we, dreamers, and world might be shattered, leaving us defenceless and dysfunctional.

All-inclusive (anamnetic) – It must encompass, integrate and incorporate all facts known about protagonist.

Coherent – It must be chronological, structured and causal.

Consistent – Self-consistent (its subplots cannot contradict one another or go against grain of main plot) and consistent with observed phenomena (both those related to protagonist and those pertaining to rest of universe).

Logically compatible – It must not violate laws of logic both internally (the plot must abide by some internally imposed logic) and externally (the Aristotelian logic which is applicable to observable world).

Insightful (diagnostic) – It must inspire in client a sense of awe and astonishment which is result of seeing something familiar in a new light or result of seeing a pattern emerging out of a big body of data. The insights must be logical conclusion of logic, language and of development of plot. Aesthetic – The plot must be both plausible and "right", beautiful, not cumbersome, not awkward, not discontinuous, smooth and so on. Parsimonious – The plot must employ minimum numbers of assumptions and entities in order to satisfy all above conditions.

Explanatory – The plot must explain behaviour of other characters in plot, hero's decisions and behaviour, why events developed way that they did.

Predictive (prognostic) – The plot must possess ability to predict future events, future behaviour of hero and of other meaningful figures and inner emotional and cognitive dynamics.

Therapeutic – With power to induce change (whether it is for better, is a matter of contemporary value judgements and fashions). Imposing – The plot must be regarded by client as preferable organizing principle of his life's events and torch to guide him in darkness to come.

Elastic – The plot must possess intrinsic abilities to self organize, reorganize, give room to emerging order, accommodate new data comfortably, avoid rigidity in its modes of reaction to attacks from within and from without.

In all these respects, a psychological plot is a theory in disguise. Scientific theories should satisfy most of same conditions. But equation is flawed. The important elements of testability, verifiability, refutability, falsifiability, and repeatability – are all missing. No experiment could be designed to test statements within plot, to establish their truth-value and, thus, to convert them to theorems.

There are four reasons to account for this shortcoming:

Ethical – Experiments would have to be conducted, involving hero and other humans. To achieve necessary result, subjects will have to be ignorant of reasons for experiments and their aims. Sometimes even very performance of an experiment will have to remain a secret (double blind experiments). Some experiments may involve unpleasant experiences. This is ethically unacceptable.

The Psychological Uncertainty Principle – The current position of a human subject can be fully known. But both treatment and experimentation influence subject and void this knowledge. The very processes of measurement and observation influence subject and change him.