By David Howes
“The inner senses or inward wits,” writes Simon Kemp in Medieval Psychology, “were psychological faculties that, throughout the Middle Ages, were assumed to be located in the ventricles of the brain”
These ventricles were supposed to be sense organs performing functions such as remembering or imagining in the same way that the eye was responsible for seeing or the ear for hearing. The theory was created by assigning the various perceptual and cognitive facilities [sic] identified by Aristotle in his De Anima to the spirit-filled cerebral ventricles described by Galen in his discussion of the anatomy of the brain (Kemp 1990: 53)
According to Kemp, the doctrine of the inner senses received its most complete expression in the works of Avicenna. Avicenna apportioned the common sense and imaginative faculty to the front and rear respectively of the front ventricle, he assigned the cogitative faculty and estimative faculty (or instinct) to the front and rear of the middle ventricle, and attributed the memory to the rear ventricle of the brain. Two further observations of note: in earlier iterations, the common sense is sometimes included among the inner senses, and sometimes left out (see Ryan 1951; Heller-Roazen 2007). This history of flitting in and out of focus may be attributed to the common sense being neither “external” nor “internal” but rather relational, the boundary sense, in Aristotle’s own writings. It was given an internal slant by some of Aristotle’s commentators (most notably the Stoics), but not Aristotle himself. Second, Avicenna, by characterizing the common sense as the “central power” basically inverted Aristotle’s conception of it as shared – that is, as parted, not centred (see Heller-Roazen 2008: 40-45).
Kemp goes on to observe that the doctrine of the inner senses, thanks to its linear arrangement of the ventricles, anticipated the “information-processing” model of modern psychology: “incoming sensory information is transformed or processed in stages, and the output of each stage or level of processing becomes the input for the next” (1990: 60). But this was purely by chance, Kemp (1990: 58) says, since, if the truth be known: “Not only is the doctrine completely false in its physiological aspects – the ventricles of the brain fulfil no psychological functions at all – but also the adoption of the doctrine meant that the rational soul had many of its psychological [read: cognitive] functions stripped from it.” Rather than bemoan the restricted role of cognition in Medieval conceptions of the psyche, Kemp should marvel at how extensive was the role of perception. Cognitive processes were sensuous processes, and not to be reduced to the operations of some disembodied intellect.