To qualify as a "psychological" plot, it must be:
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.
Uniqueness – Psychological experiments are, therefore, bound to be unique, unrepeatable, cannot be replicated elsewhere and at other times even if they deal with SAME subjects. The subjects are never same due to psychological uncertainty principle. Repeating experiments with other subjects adversely affects scientific value of results. The undergeneration of testable hypotheses – Psychology does not generate a sufficient number of hypotheses, which can be subjected to scientific testing. This has to do with fabulous (=storytelling) nature of psychology. In a way, psychology has affinity with some private languages. It is a form of art and, as such, is self-sufficient. If structural, internal constraints and requirements are met – a statement is deemed true even if it does not satisfy external scientific requirements.