It was getting dark by the time the dog and I reached the old mine at the top of the hill, so I took a shortcut back through the gorse, throwing sticks into the gloom along the way. The dog returned with one I hadn't thrown. It was a rotting log rather than a stick. I took it and tried to lodge it in a bush out of reach but the dog leapt and snapped, catching my finger. The pain struck like an electric shock; no, it burned like a blowtorch; no, it fizzed like acid. I don't know what it was like exactly, but Fucking Hell It Hurt. I shaped to kick the animal, but didn't. She wagged her tail. I examined my right index finger and saw that the bite had left a ragged puncture hole at the edge of the fingernail, cracking the nail to the quick. I wound a handkerchief round it and headed for the local minor injuries unit. On the way home, I collected a prescription for some prophylactic antibiotics.
The injury was trivial, but inordinately painful. As torturers appreciate, the soft tissues beneath the fingernails are rich in pain receptors. One of the puzzles of pain is that the severity of suffering has an uncertain correlation with the extent of damage to the body. David Livingstone famously described being mauled by a lion. "Growling horribly close to my ear, he shook me as a terrier does a rat." His arm was chewed up and his shoulder bones splintered, but he felt neither pain nor terror. Bathed in a flood of stress-induced analgesic hormones and neurotransmitters, he describes entering a state of resigned tranquillity. Nature is full of creatures being eaten alive, he thought, and this is God's way of making it tolerable for the victims. God does His bit on the battlefield and the roadside, too. Soldiers often express bemusement over the relative painlessness of having a limb blown away. And I remember interviewing a patient whose arm had been torn off in a motorcycle accident. He had lost consciousness momentarily and when he opened his eyes it took him a while to realise that the object lying some distance away in the ditch was his arm. He handed it over to one of the paramedics when the ambulance arrived. There was little pain.
Sometimes the converse happens: severe pain without injury. My patient, John complained of thumping headaches, excruciating stomach cramps, sore feet, sharp stabs at the small of his back, and burning fingers. The constellation of symptoms was meaningless and all medical investigations proved negative. I had run out of ideas and suggested he might be depressed. He disagreed and gave up on me. But a couple of weeks later his wife called. John was in a bad way, she said. He was weeping with the pain, and the grief. Grief? It was the anniversary of their son's death. I had done a routine family history but there had been no mention of a dead son. John's sorrow had entered his bones and his guts.
Hypersensitivity to bodily feelings is common in some forms of depression. The brain receives a constant supply of sensory information from the entire surface of the body and from muscles, tendons and joint receptors. Then there are sensations arising from the internal organs - heartbeats, rumblings in the bowel, "butterflies" in the stomach. Close your eyes and a spectral image of your body takes shape. You sense the position of your limbs, torso and head. You become aware of areas of warmth and cold, the rising and falling of the rib cage, points of contact with clothing and other objects, varying states of muscular tension, mild aches and itches. This is the sensorium of the body image, the workshop of self-awareness; but it operates at the periphery of consciousness. Mechanisms of selective attention screen out the majority of sensory inputs. The body is mostly absent. Pain makes it present. The gentle promptings of the sensorium become angry shouts. In John's case benign sensation transmutes to pain, the sensorium becomes a cacophonous torture chamber.
Pain pulls down the wall of Cartesian dualism - the one that falsely separates mind and body. It is a hybrid without a natural habitat in textbooks of neuroscience and psychology. One of the body senses, it also fuses with emotion (like fear, pain is intrinsically unpleasant) and motivation (it is to be avoided). Clinically, too, the boundaries are uncertain. It merges with malaise and with forms of emotional distress that lack any foundation in bodily damage. The language of pain reflects these dimensions. There are words for the sensory components ("sharp," "crushing," "burning") and others for emotion ("fearful," "punishing," "wretched"). But to verbalise pain too precisely is to dilute the effect, I think. As far as my finger is concerned, Fucking Hell It Hurt comes close enough.
With my finger still bandaged, I took the dog out again this afternoon. I took satisfaction in curbing my burst of anger the other day. But, I wonder, if I had kicked her would she have suffered? Descartes believed all animals to be unconscious automata. Some contemporary psychologists and philosophers take the same view. A dog yelping in pain is like the chiming of a clock. Given her cheerful tail-wagging in the face of my distress perhaps the dog feels the same about me.
