We are fragile beings, here temporarily and ever hopeful that we will make the most of our stay in life, to the very end. Not a bitter end, but a sweet drift from everything we know. I was listening to John Suchet on BBC Radio 4 this morning in the sub zero beauty of the Pyrenees, talking about his wife Bonnie and how she was being taken from him by Alzheimers. How he has spilled into anger occasionally at her increasing ineptitude – with all the resulting guilt.

It brought back to me The Man Who Mistook His Wife For A Hat by Oliver Sachs. You may have read it, but if not, it is a series of well-written, wry case studies of people with personality problems which have resulted from brain lesions, cerebral diseases and rare conditions that impair a person’s sense of self. In it are people who live in micro worlds of short term memory so that everything is experienced and forgotten within minutes, people who have no sense of self in space (proprioception) and have consciously to keep their eyes open and tell themselves what to do with every bit of their bodies or they will collapse in a heap and people who mistake and confuse every day objects to such an extent that life becomes an impenetrable series of perplexing labyrinths. What Sachs suggests is that, despite the severity of these conditions, there is something, some essence that remains which is quintessentially human, even if the personality of the individual has fled the brain.

The false belief at the heart of the fragility, it seems to me, is the notion that we have a unity which we call the self. The reason, perhaps, is probably our need to be social creatures, consistent, coherent, relatively easy to get on with, so that we become stereotyped in our habits, attitudes, behaviours. People then think they know us, and so we present no threat. If this uniformity begins to break down and our acts become inexplicable, then we become social problems. We present a picture of ourselves to the world that is incompletely human.

What to make of it? There would hardly be an individual among us who would want to face the slow extinction of the personality, even allowing for the fact that after some point in the disintegration we wouldn’t be aware of it. It comes back to the clichéd question of Who are we? If a disease can rob us of our personality then was it a mere chimera in the first place? An illusion? What held it held together for so long, anyway? All those cells in the brain and body interacting chemically and electrically, conspiring to project on the screen of the mind the wavering image that each of us are taught to think of as the self. No wonder we embrace religious convention to give us the potential comfort of a meaningful life now and a Hereafter where this wavering montage coalesces into a heavenly form. It is too painful to feel that our entities are merely the result of the capriciousness of tiny cells.

And these same cells make us empathise with John Suchet, feel for his terrible dilemma, and write reactions to it just like this.