杏吧原创

In The Mind鈥檚 Eye, the neurologist explores case histories of people with visual disturbances 鈥� including his own

WHAT would it be like to occupy the brain of a non-human being? This is a question that has inspired writers (Franz Kafka鈥檚 Metamorphosis), philosophers (Thomas Nagel鈥檚 鈥淲hat is it like to be a bat?鈥�) and just about every curious human being. It is this curiosity about different forms of being that helps explain our fascination with the writings of Oliver Sacks.

Although Sacks鈥檚 books generally deal with altered states, this new one on visual experience brings it home more clearly because, for the sighted among us, 鈥渨hat it鈥檚 like to be鈥� tends to get fleshed out visually. The Mind鈥檚 Eye takes up stories of individuals who have lost visual capabilities, such as object recognition, face recognition, reading and stereoscopic depth.

The book excels in its descriptions of 鈥渁ltered states鈥�, to be sure, but there are other, more obvious, reasons why we like Sacks鈥檚 writing about neurological disorders. First is that they illustrate how the everyday tasks we carry out are in fact fantastically complex and rely on equally complex brain mechanisms. A close, and related, second is that his stories indicate our brain鈥檚 specialisations, leading us to respond, 鈥淲oah, I didn鈥檛 even know I had brain regions for that!鈥�

A more emotional attraction to Sacks is that his stories are simply great stories 鈥� he even got my neurologist wife and I teary as she read to me on a road trip the case of Patricia H.鈥檚 loss of language and her use of gestures to partially compensate. These are stories about the human spirit attempting to overcome a piercing blow to what it means to be human.

The appeal of Sacks鈥檚 style isn鈥檛 just that it is neurobiologically illuminating and poignant. It鈥檚 also grist for the philosopher in us. Wondering what it鈥檚 like to be an alien, dog or bat can be entertaining, but any answers found are likely fiction. Sacks鈥檚 stories, on the other hand, get us into the heads of beings who experience a truly alternative form of being and are able to communicate what it鈥檚 like.

The fact that these alternative forms of being are accidental cases may make it all the more interesting. The space of possible ways of being is vast compared with the space of ways of being that may plausibly be selected for in evolution. For those with an itch for altered states, seamless psychological design and fit with a given habitat can be beside the point.

Among the 鈥渁ccidental ways of being鈥� described in The Mind鈥檚 Eye, one stands out: Sacks鈥檚 own struggle with vision loss due to ocular melanoma, including its consequences for visual neglect, stereoscopy and the perception of one鈥檚 own limbs, including visual phantom limbs. One only hopes Sacks鈥檚 personal tour into altered states is at its end.