This fifth chapter of Iain McGilchrist’s latest book, The Matter With Things, is short; only 10 pages long, compared to some chapters which are almost book length; for example, Chapter 28 is more than 100 pages long.
In Chapter 5 McGilchrist takes a different approach to that taken in preceding chapters in that instead of examining what happens after right hemisphere damage, here he focusses on what happens after left hemisphere damage. This is in relation to the left hemisphere’s propensity to manipulate the world by grasping or holding on to it, i.e., to apprehend it, as opposed to the right hemisphere’s propensity to encounter the world, explore it and hold things together, i.e., to comprehend it.
McGilchrist doesn’t explain why he took this different approach. Perhaps there is more evidence of what happens after left hemisphere damage, but I found myself wondering how the chapter might have been different had it been titled Comprehension instead of Apprehension.
As ever, McGilchrist shares his understanding of the etymology of the two words.
Ap-prehending, from Latin ad + prehendere, to hold onto – manipulating
Com-prehending, from Latin cum + prehendere, to hold together – understanding
I always find McGilchrist’s explanations of the origins of words helpful in understanding how he interprets and represents them. So, from this, the left hemisphere apprehends and the right hemisphere comprehends. When there is damage to the left hemisphere the world is still there and comprehensible, but it can no longer easily utilise the world or represent it. The simple act of utilisation is lost. We see this in left hemisphere stroke patients whose right arm and right hand function is impaired. McGilchrist uses further patient vignettes to illustrate this point that left hemisphere damage leaves the patient unable to use simple tools such as a key or a toothbrush.
The right hemisphere explores with the left hand. This behaviour can be seen in the great apes that use the right hand to grasp something, but the left hand for making contact with others. Right hemisphere damage rarely results in an inability to use tools, but instead affects the patient’s ability to perform a sequence of tasks to achieve an end, for example, make a cup of coffee.
When the left hemisphere is damaged, as in a stroke, not only is the patient’s right arm and hand function impaired, but also their use of language. McGilchrist suggests that the left hemisphere uses language to map the world, i.e., it uses language to manipulate the world and maps the territory through the use of a system of symbols. But a map leaves most of the world out. ‘In the left hemisphere’s world words are seen as arbitrary signs: in the right hemisphere’s world they are seen as to some extent fused with the aspect of reality they represent.’ (p.185). The right hemisphere sees the reality of the terrain it maps. In the left hemisphere signs are substituted for experience, but the aspects of language that tether it to the lived world, and the body, metaphor, prosody (the inflection of the voice, the sound of the word and the meaning conveyed), and pragmatics (understanding utterances in context) are right hemisphere dependent.
Left hemisphere damage doesn’t alter reality; the world is still there but a left hemisphere damaged patient can’t use it. Damage to the right hemisphere causes alterations in reality.
The purpose of the left hemisphere is to become powerful, not to understand reality. Damage to the left hemisphere results in loss of this power to utilise and manipulate the world through the right hand and language, but reality remains largely unaltered.
For a discussion about this chapter between Iain McGilchrist and Alex Gomez-Marin watch this video
McGilchrist, I. (2021). The Matter With Things. Our Brains, Our Delusions, and the Unmaking of the World. Perspectiva Press.