Aetiology and the problem of understanding individual causes

It is helpful to begin by thinking just what the social aetiology of mental illness implies about the connection between social factors and mental illness. Does it mean that the social factors cause or are constitutive of mental illness? The former view is consistent with a bio-medical view of illness (as underpinned by something being wrong within the body) even if that model has sometimes neglected social causes. But there is genuine inconsistency if what it is to be ill is to be, for example, out of step with one’s community, whatever happens in the body. That is a constitutive view. We will return to it in the fourth and fifth sessions.

A second preliminary question is whether social factors brutely cause mental illness or whether we expect the link to be understandable: mental illness as a kind of half rational response to life events. If it is the second view, then that suggests a role for understanding as opposed to explanation. We will return to that in the second session.

This session will put the practical problems of establishing the aetiology of illness and disease (with which students will already be familiar) in the context of the principled problem identified by Hume of seeing causal connections in even the best possible circumstances. The simplest idea of a social aetiology of mental illness is one of social causes. But what does that idea commit us to? It is often helpful in complex cases to try to strip away the practical complexities and think about the underlying ‘logic’ of the situation.

Hume’s investigation of the concept of causation reflects his empiricist view of the mind. He believed that the mind was populated by ideas and impressions. Complex ideas were based on simple ideas and (nearly!) every simple idea was drawn from a corresponding ‘impression’: an experience. Our idea of causation seems to be that of one event making another event happen. If that is right, it should be possible to find an impression of one event making another event happen. But that does not seem to be the case.

If it is not, what do we mean by ‘cause’? And what kind of connection should we find between social causes and mental illness effects?

In the last few years, the influential philosopher John Campbell has written some papers on the application of cause-effect relationships in psychology and psychiatry. He draws on Hume's discussion of causation although he also subscribes to an interventionist view of causation (according to which a key idea is that if one things causes another then intervening to change the former is a way to change the latter). But a key negative moral is that Hume teaches us - correctly - that causation is brute. And hence, there is no a priori rationale for thinking that causal explanation works at intuitively intelligible levels. He gives, as an example, a discussion of thought insertion by Christopher Frith. Frith claims that whether or not inappropriate firings of dopamine neurons are found in subjects who experience thought insertion, that fact cannot be used to explain their experiences as it would shed no light on why that kind of symptom, rather than another, was produced by such firing. To shed light, Frith assumes, we need an account pitched at a particular level: in Frith’s case that of a sub-personal but still cognitive model of mechanisms supposedly responsible for thought insertion. Campbell suggests that the assumption that there is a right level of explanation which clarifies things in the way Frith desires is the result of a pre-Humean view of causal explanation. Although it is easily forgotten, Hume taught us that there need be no intelligible connection between cause and effect. That is implicit in his rejection of any logical connection to analyse the necessitating relation between them. But is such an austere view appropriate for the causal understanding of mental illness?

Essential reading

    • Fulford, K.W.M., Thornton, T. and Graham, G. The Oxford Textbook of Philosophy and Psychiatry Oxford: Oxford University Press chapter 15 session 1 as far as p412 (including readings)

    • (The discussion continues for 5 more pages from 412-7 looking in more detail at what it means to say, eg., that a spark caused a fire and the nature of laws of nature and how they differ from generalities which merely happen to be true)

Further reading

  • Campbell, J. (2008) ‘Causation in psychiatry’ in Kendler, K.S. and Parnas, J. (eds) Philosophical Issues in Psychiatry, Baltimore: Johns Hopkins University Press

  • Campbell, J. (2009) ‘What does rationality have to do with psychological causation? Propositional attitudes as mechanisms and as control variables’ in Bortolotti, L. and Broome, M. (eds) Psychiatry as Cognitive Neuroscience, Oxford: Oxford University Press

    • Rizzi, D.A. (1994) ‘Causal reasoning and the diagnostic process’ in Theoretical Medicine 15: 315-333

    • Hume, D. (1975) Enquiries Concerning Human Understanding, Oxford: Oxford University Press sections II and III pp17-24.

    • Thornton, T. (2007) Essential Philosophy of Psychiatry, Oxford, OUP chapter 5.

This session’s lecture slides are here. Further, additional, relevant slides can be found via this page.

Reflections on this session are here

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