I N THEIR attempts to cope with the ill-defined nature ofcontemporary psychiatric theory and its lack of a firm, comprehensive foundation, psychiatrists have constructed 'models', 'systems', all-embracing frameworks within which the mechanisms and processes of thought and behaviour, rational and irrational, are explained and understood. Inevitably, in a field that lacks the solid, tested, theoretical base of a natural science, such as physics, and that has yet to achieve the impressive pragmatic achievements of a clinical science, such as medicine, individual psychiatrists fall prey to the temptation to adhere to this or that explanatory system with a dogmatism redolent of religious fanaticism. There is, in addition, a slow, gradual, and pervasive influence exerted by such stout believers so that students in psychiatry are often led to feel that it is only because of resistance or prejudice on their part that they cannot see the truth of what their teachers affirm with such conviction.