Development of the concept of mind.

A short account is given of the development of concepts of soul, mind and brain in order to place in historical context the subject of neuropsychiatry. A selection of primary and secondary historical sources is used to trace development of these concepts. Beginning with the spirits of Animism in the 3rd millennium BC, the Greek invention of the soul and its properties, of thymos (emotion), menos (rage) and nous (intellect) are then traced from the time of Homer, in which the soul does not last the death of the body, to Plato in the 4th century BC who argued that the soul, incorporating the nous (now called mind) is incorporeal and immortal. Plato's pupil, Aristotle, commented on the impossibility of an incorporeal soul interacting with a corporeal body. He instituted a revolution in the concept of mind. This involved pointing out that 'mind' is a manner of speaking about our psychological powers as in thinking and remembering. Given that such powers are not a thing the problem does not arise as to the relation between mind and a corporeal body. These ideas of Plato and Aristotle were held by competing scholars and theologians during the next 2000 years. Plato was favoured by many in the Church who could more readily grasp the concept of an immortal and incorporeal soul within the context of Christian thought. Galen established in the 2nd century AD that psychological capacities are associated with the brain, and argued that the fluid-filled ventricles were the part of the brain involved. This argument stood for over 1500 years until the 17th century when Willis, as a consequence of the new blood perfusion techniques developed by Wren following Harvey, showed that blood did not enter the ventricles but the cortex, thereby transferring interest from the ventricles to the cortex. The hegemony of Plato's ideas was broken about this time by Descartes when he argued that the incorporeal soul does not consist of three parts (thymos, nous and menos) but is solely identical with the mind, which is not just concerned with reasoning but with perception and the senses, indeed identical with consciousness 'taken as everything we are aware of happening within us'. The shadow cast by this concept, necessitating as it does relating the Cartesian mind to the cortex, stretches from the time of Willis, through to the foundation figures of neurophysiology and psychiatry in the early 20th century, namely Sherrington and Kraepelin, and beyond. This history is traced in detail because the Cartesian paradigm provides the main resistance to Kraepelin's argument that mental illness has biological concomitants. It is argued that the modern tendency to equate the mind with the brain does not illuminate the problem that was solved by Aristotle. The mind is not as either Plato of Descartes would have it, nor is it equivalent to the brain, for talk of the mind is a manner of talking about human psychological powers and their exercise, as in 'mind your step' (watch where you are going), 'keep that in mind' (remember it). It is suggested that the history of the concept of mind shows that a human being has a corporeal body and a mind, that is, a range of psychological capacities. It is the role of neuropsychiatry to identify the changes in the corporeal that need to be put aright when these psychological capacities go awry.