Section VII Explanation and understanding
For much of its history, the pairing of explanation and understanding has been taken to express an opposition between natural science and human science or interpersonal understanding more broadly. Further, the opposition was taken to express the limits of both. The kind of insight offered by one was impossible to achieve by the other. This was Jaspers’ view. Whilst psychiatry should contain both approaches, and whilst the very same events could be approached using either (he thought that every event could, in principle be explained and, more surprisingly, all could also be understood), concentration on only one risked diminishing the insight.
Given that understanding is an implicit thread through much of the rest of this handbook, this section concerns not what cannot but rather what can be studied scientifically. On the assumption that psychiatry is based, in part at least, on natural science, what is the nature or the general shape of that science? Some of the chapters aim at getting right the nature of component parts of a scientific world view. What, for example, is the nature of causation and its connection, if any, to the existence of mechanisms? If psychiatry rests on a taxonomy of mental disorders, what kind of kinds does that involve? If they merit the title ‘natural kinds’, what exactly are those? Should taxonomy aim at reliability and validity and are these in tension?
Others concern potentially fruitful scientific approaches. One chapter addresses not a priori arguments against the identity in principle of mind and brain but rather what concretely can be learnt about the mind from sub-personal brain mechanisms studied using contemporary imaging techniques. Another addresses how phenomenology – the philosophical approach with which Jaspers was familiar – can be combined with neurology to produce a unified discipline which augments both.
The overall moral of the section is that psychiatry can properly claim to contain – if not be restricted to – a scientific discipline but one which requires a twenty first philosophy of science. The conception of science which dominated philosophy at the start of the twentieth century assumed that things were much simpler than they have proved to be. That conception was a poor fit for a discipline facing the empirical and conceptual challenges that psychiatry has taken on. Once, however, one realises that there can be different kinds of (natural) kinds; that causal links need not be restricted to well behaved levels of explanation but can cross levels (if, indeed, such talk of levels fits actual findings); that there are varieties of validity and reliability with opposing virtues etc. then one has a more appropriate understanding of the nature of science to shed light on psychiatric practice.
In ‘Causation and mechanisms in psychiatry’, John Campbell returns to a theme he has been developing in a number of recent papers on psychiatry and psychology. Taking the question of whether poverty causes mental illness as a first example, he argues against some assumptions that have been taken to constrain causation and then for a positive view. There is no need to assume that only particular kinds of cause can have particular kinds of effects belonging to the same ‘level of explanation’. Second, although we find it natural and fruitful to look for them, there need be no mechanisms mediating cause and effect. But third, causation can be thought of in the light of potential interventions. In the example given, if intervening on poverty has effects on mental illness then poverty – possibly brutely – causes mental illness.
Rachel Cooper argues in ‘Natural kinds’ that debate about whether mental disorders can be natural kinds has been distorted by assuming that such kinds have to be like the kinds picked out by the Periodic Table in chemistry. There are, however, different views of kinds in different natural sciences (eg kinds of rock in geology). In consequence, Cooper argues for a relaxed view in consequence: natural kinds are kinds picked out by the sciences. Such kinds, of whatever sort, can ground explanations and predictions. Thus, although kinds of mental disorder differ from the kinds recognised by sciences such as chemistry in various ways, they may yet be natural kinds.
The first challenge Dominic Murphy addresses in ‘The medical model and the methods of cognitive neuroscience’ is to characterise what the ‘medical model’ might mean especially in the context of psychiatry. He distinguishes a minimalist from a stronger version. The former adopts appropriate empirical methods, such as epidemiology or evidence of dose-response relationships for drugs and is ‘recognisably medical in terms of the information it collects, the concepts it employs and the practices it supports’. But it ‘makes few, if any, commitments about what is really going on with the patient’. By contrast a stronger version adds to this a commitment that disease is a breakdown in normal functioning due to a pathogenic process unfolding in some bodily system. The chapter then explores how such a view of psychiatry as an instance of cognitive neuroscience concerned with the sub-personal causes of psychiatric signs and symptoms can address issues such as the proper level of explanation and or the value-based nature of illness..
Ken Schaffner’s ‘Reduction and Reductionism (in Psychiatry)’ is still to come...
In ‘Reliability, validity, and the mixed blessings of operationalism’ Nick Haslam starts by providing careful overview of the various concepts of reliability and validity and explores their interrelation. He then uses this to assess the benefits and the costs of the reliability inspired turn to operationalist diagnosis begun in DSM III. Although nuanced, he argues that whilst it may have helped to explore the relationships between diagnoses and other relevant clinical phenomena and also improved communication across theoretical and cultural divides, it may also have contributed to the proliferation of mental disorders, the resulting problem of comorbidity, and a distorted conception of some forms of psychopathology where its focus on observable features may have led to a systematic neglect of others.
J.D. Trout and Michael Bishop’s ‘Diagnostic Prediction and Prognosis: Getting from Symptom to Treatment’ looks first at diagnosis and then prognosis and treatment. The first half provides an overview of the evidence concerning the effectiveness of a variety of approaches to diagnosis starting with subjective methods, semi-structured and structured clinical interviews and Statistical Prediction Rules (SPRs). It transpires that the last approach trumps all others: ‘when based on the same evidence, the predictions of well-constructed SPRs are at least as reliable, and are often more reliable, than the predictions of human experts’. The second half of the chapter discusses assessment of the effectiveness of treatments including a discussion of what counts as a placebo control in the case of talking therapies.
Tim Thornton’s chapter ‘Clinical judgement, tacit knowledge and recognition in psychiatric diagnosis’ takes Michael Polanyi’s famous slogan that ‘we know more then we can tell’ and his discussion of knowledge of anatomy to assess the role of tacit knowledge in psychiatric diagnosis. Against a view of tacit knowledge as context-dependent and practical, it argues for its ineliminable role in diagnosis even in cases of very thorough phenomenological description.
Two chapters, in different ways, sketch the possibilities for particular scientific approaches to the study of mind. Nicholas Shea argues in ‘Neural mechanisms of decision making and the personal level’ that more general philosophical arguments concerning the relation between personal and sub-personal level descriptions (eg Davidsonian arguments that personal level descriptions cannot be reduced to sub-personal level descriptions) leave open the possibility that light can be shed on the nature of human experience through neural imaging work. He outlines one particular study of neural basis of reward-guided decision making in which imaging suggests that a particular psychological approach or model is realised in the imaged brain activity. Shea goes on to outline how such an approach might also shed light on addiction and schizophrenic delusions.
In ‘Psychopathology and the enactive mind’ Giovanna Colombetti sketches account of recent enactivist approaches to the mind, which draws on the phenomenology of Merleau-Ponty but also neuroscience. Specifically, she outlines the interplay of three key themes in enactivism: the ‘neurophenomenological’ integration of first- and third-person data concerning lived experience and physiological activity for the study of consciousness; its emphasis on the integration of cognition and emotion and the direct bodily and affective nature of intersubjectivity.
The final chapter of the section, Michael Lacewing’s ‘Could psychoanalysis be a science?’ addresses its titular question. Although the particular issues outlined concerning the characteristic forms of psychoanalytic theory and practice and the way evidence for it can be marshalled both on its own terms and in combination with other approaches are distinctive, the chapter also serves as a microcosm for the issues that face psychiatry more broadly when critics ask about its scientific status.