How good is psychotherapy as a tool of research into human nature? There is an orthodox defence of it as a research tool, which relies on showing that interpretations are true of the patient when they satisfy certain criteria. This defence is examined and rejected. The reply is considered that an interpretation which 'keeps things moving' is true, or an approximation to the truth. This reply is rejected by comparing and contrasting an interpretation in psychotherapy with one from brainwashing sessions. (...) Two suppositions about psychotherapy (which weaken its discovery powers) are deliberately adopted — the suppositions that the material produced is 'perspective' and 'method' dependent. An unorthodox defence of psychotherapy is then offered — by means of a watery sense of 'discover'. This enables us to outline a weak sense in which psychotherapy is a valid enterprise, but one which is still strong enough for research purposes. (shrink)