The author discusses the ways in which psychoanalytic theories, like other theories, attempt to systematise the understanding of observations. Freud remarked that systems also have unconscious meanings. The author discusses these unconscious vicissitudes of psychoanalytic theories of both clinical and more abstract kinds, at various levels of psychological function. Learning psychoanalysis repeats in some respects the developmental processes of learning about 'reality'. The role of authority and superego function in learning and utilising theories is emphasised. The enduring unconscious relationship of theory to authority contributes to adherence to, misapplications of, and rejection of theories, as well as to anti-theoretical attitudes. The concept of an 'analysing instrument' illustrates the way in which a useful exploratory idea may acquire prescriptive and constrictive implications. Analysis of the analyst's attitudes towards theory and its applications is an aspect of countertransference analysis.