The True and The Helpful: Lessons from Psychotherapy

In recent years, philosophy of psychiatry has moved away from traditional areas of inquiry such as questions of nosology and the demarcation of mental disorder, to more wide ranging debates concerning the relationship between rationality and mental health. For instance, though one might think mental disorders involving delusions, such as schizophrenia, clearly involve failures of epistemic rationality, the work of Lisa Bortolotti demonstrates the difficulty of disambiguating delusions from ordinary beliefs.

I consider a parallel problem in the characterisation of mental illness by one of the most prominent schools of contemporary therapy, Cognitive Behaviour Therapy (CBT). CBT describes mental illnesses such as depression in terms of "thinking errors", suggesting that the basis of mental disorder involves familiar epistemic errors such as unwarranted inferences and the holding of inaccurate beliefs. I will begin by demonstrating that CBT's description of mental illness is unsupported by current research, then draw some general lessons not only for questions of mental disorder but philosophical debates concerning rationality more broadly.

Briefly, I shall argue that mental disorders such as depression, if they involve failures of rationality at all, are more likely to involve failures of epistemic rather than practical rationality and that philosophical debates in rationality should reconsider their tendency to assume that epistemic rationality is somehow superior to, or 'trumps' practical rationality