Monday, April 25, 2011

self comes to mind; constructing the conscious brain - Redux

Guardian | Brains are by no means the only game in town; bacteria and plants of course flourish quite well without, and will probably outlive humans. But our ancestors took a different route, building bigger and more complex brains. Within such brains neurons communicate with each other by myriad connections. These fluctuating patterns can form representations of both the external world and the body state of the organism that owns them. Such brains enable their possessors to learn and remember, to recognise the present in the context of the immediate past and the imminent future. To Damasio this means that they are, or possess, selves. In animals with big brains, emotions – mere bodily responses – become translated into feelings, and with feelings, a mind – "a subtle flowing combination of actual images and recalled images in ever-changing proportions" – emerges from the brain. Many large-brained creatures thus have minds, however alien they may be to our own. But consciousness emerges only when – to quote the book's title – self comes to mind, so that in key brain regions, the representational maps of sensory experience intersect with the encoded experiences of past that self provides. This, enabled by the evolution of language, makes possible autobiographical memory – the narrative of our lives that we humans all possess and which is the basis for consciousness.

This, briefly summarised, is the latest version of Damasio's theory. The story is told in prose of intermittently easygoing lucidity, but his primary training as a neurologist compels him into passages of detailed neuro-anatomy, locating brain regions functionally responsible for enabling particular aspects of consciousness. But which bits of the brain might be involved, though of passionate concern to neuroscientists, isn't the crucial issue – which is whether Damasio has thereby solved what has been called the "hard problem" of consciousness studies by relating third-person "objective" accounts to first-person subjectivity. I fear that however convincing his evolutionary story may be, simply to state that these brain processes translate into mental experience leaves us, despite some very elegant hand-waving, exactly where we were before. And herein lies the paradox of the book's subtitle. Brains are not conscious; people are. Our brains enable our consciousness, just as our legs enable our walking, as the anthropologist Tim Ingold has pointed out. But to attribute the property of a whole to that of a part is to commit what philosophers refer to as the mereological fallacy (one that I confess I have not been entirely innocent of in my own writings).

In everyday thought and speech we have reasons, intentions, feelings. In brainspeak we have synapses, firing patterns, neurotransmitters. For the mechanical materialist, the latter causes the former – and in his routine use of causal language Damasio reveals himself as just that. This is why the weakest part of the book is the concluding chapters, where he extends his central principle of homeostasis to embrace human history, society and culture. But it is possible to be a non-reductionist materialist. The language of mind and consciousness relates to the language of brains and synapses as English does to Italian; one may translate into the other, though always with some loss of cultural resonance. But we do not have to assign primacy to either. Long may pluralism reign, and we conscious beings continue to employ our minds and brains to enhance our understanding of both.