There is a long-standing dispute as to the type of knowledge that should serve as the foundation of psychoanalytic and psychodynamic practice and research. This dispute encompasses both a theoretical problem - what is the nature of psychoanalytic/psychodynamic knowledge - and a practical one: what sort of knowledge does the therapist rely on while sitting with his or her patients. There is one approach that deems it necessary that this knowledge be grounded in objective and systematic evidence derived from controlled experiments that can be replicated. Another sees knowledge of the human mind and the therapeutic action as immeasurable, and argues that the knowledge that is required should be derived from a thorough familiarity with the vast range of psychoanalytic theories combined with personal and communal experience, and that knowledge of the therapeutic action should be rediscovered in each and every patient - therapist encounter. This paper tries to characterize these two kinds of knowledge, examine their philosophical underpinnings, and formulate a ‘language’ - ‘the language of Phronesis’ - which attempts not only to hold within it both these forms of knowledge but to see them as mutually enriching and fertilizing.