I've often wondered how I would withstand great pain. I mean the pain of the body, that which registers on the nerves, not that of loss or deprivation that ravishes our emotional life.

When the pain came, would I behave with some amount of stoicism and even grim humor, like the protagonists in Hemingway novels whom I so admired? Or would I moan and howl in sounds far beyond intelligible human speech?

Last year I found out when a kidney stone made its slow passage through my right ureter. You may not know what ureters are -- certainly you wouldn't be too aware that you possessed them until a bit of solid matter larger than the ureter's diameter left your kidney for the journey to the outside world.

This journey can begin suddenly, with paralyzing force. "Like being hit with a two-by-four," one friend told me. "Like being shot with an arrow," said another. But no simile can adequately describe pain, or pleasure for that matter; it must be experienced. We can know the concrete causes of pain, like pressure, too much heat, the splitting of the flesh, but the resultant pain is an abstraction, and like all abstractions it lies beyond the precise grasp of language. We simply don't have the words. We can have trouble, then, describing our own pain and another's pain, even when it manifests itself in grimacing, say, or writhing. Ultimately it remains metaphysical -- something to doubt.

My kidney stone "attack" tugged me from an uneasy sleep at 3:07 a.m. The pain was then only a few degrees beyond uncomfortable, and I thought for some hopeful minutes that I might have a strange muscle cramp or that my innards were protesting against the odd-tasting tofu burger I had risked for dinner. I tried to ignore it. I tried to force my thoughts elsewhere. But the pain was insistent. I massaged my side and twisted this way and that, but no amount of repositioning or rubbing relieved the hot spike tunneling through my abdomen.

The pain ascended through the long hours of the early morning toward a level that dwarfed all the other pains I had known before, including an abscessed tooth and torn ankle ligaments. It nearly equaled the spectacular sensation of bringing a hammer down upon my thumb, but that was brief in comparison, a few minutes of localized agony that then settled into a bearable throbbing. The pain in my side was not just severe but unrelenting, a continuous deep gnawing coupled with cold sweats, nausea and other blades of pain that radiated throughout the confused coils of my digestion, causing more mischief there.

I paced the length of the house, took a hot bath, tried some yoga and breathing exercises taken from a dusty New Age book I had once purchased as a cure for all my ills. I pulled my hair, pressed my temples, bit my fist. Before all emotions left me, I cursed with a flamboyance that, were I loud enough, would surely have caused the houseplants to wilt. At one point, I curled up on the floor like the insensate fetus I wished then to be. But no measure I took lessened the pain.

When the sun fully rose, I was still in pain, and still grinding my teeth against it some hours later in the emergency room of a local hospital. A nurse inserted a shunt into the back of my hand and hooked me up to an I.V. meant to flush the stone from my plumbing. It would be an additional hour of pain before I received a mainline of blessed Toradol. In 20 minutes, the pain began to retreat. In half an hour, I was smiling, joking with the nurse and listening to the prosaic conversations of the staff, even as other emergency cases groaned and yelped in the curtained spaces about me. But I smiled and joked because of relief, not elation. In fact, while I was still in the E.R., a peculiar despair began to creep over me.

I was still despondent when I underwent a CT scan two days later because the "calculus" was taking its time to leave my body. I had to wait an hour before the procedure, and I spent the time shivering in the thin hospital robe, my socks and loafers, looking as far from chic as a person can get. Another man waited with me. He kept his face in one battered magazine after the other. We did not speak. He seemed to want to be invisible, and so did I. There was a subtext to this business and it was a dark one.

While waiting, I thought back to the attack and how my desire for the pain to end quickly became a need exclusive of all other considerations. Family, job, achievements, passions and the like all lost their significance. The pain became more than a steel box that separated me from anything but itself, more than a wedge that drove itself between my mind and body, making me more fully, if not totally, the latter. What great pain does, I learned that long night, is obliterate memory, in fact, "all psychological content, painful, pleasurable and neutral," as philosopher Elaine Scarry writes in "The Body in Pain." When that occurs, we are no more than flesh, bone and blood. We lose our character, who we are. This is the true nature of the joy we feel at pain's cessation -- the recovery of our humanity.

Eventually, I was put into the interesting machine and it did its work. Later, still in my airy gown, I was encouraged to see the images assembled on a white screen in a darkened room. It appeared as though I had been sliced repeatedly like a large bolt of prosciutto, and I was reminded of an earlier time.

After fracturing my jaw in my early 20s while playing football, I acquired the X-ray prints of my skull from the oral surgeon. After my mouth had been wired shut and I began to dine on various puries, I'd place the X-rays against the windowpane. With equal measures of revulsion and fascination, I'd gaze upon the pencil-line break in my jawbone, my teeth with their bits of metal, the shadow of my brain.

I felt as though I were looking at my own corpse, my flesh sloughed away by time. This is what would be in my coffin some years later, I thought. The processes that went through my mind at the moment -- That's me? -- were managed by the very thing I was looking at, a picture of my gray skull's contents set starkly against a blue sky. This was unsettling, but I did not fully realize why until the internist showed me the CT scan images of my torso many years later, when I was much closer to the end of my average life span.

"There are your kidneys," he said, pointing at an image with a pen. "The right one's a little backed up from the stone, which you can see here." He pointed to a white dot near my bladder where the ureter emptied. "It's hung up. If it doesn't move within a few days, we'll have to do something mechanical."

I only nodded. I was not thinking of the "something mechanical," nor of the pain to come should the stone dislodge itself and travel. The pain had been only one component of the despair that followed my kidney-stone attack. The other, and perhaps more disturbing, revealed itself in that darkened room where I was made to confront the notion that we're all just a bunch of parts and slippery workings that are prone to failure like any other mechanism, and with pain usually added. I was also thinking of my own father's kidneys, which were destroyed by 20 years of diabetes and so killed him.

I was thinking, too, of my stepfather, who had died of cancer several years ago after a kidney stone sent him to the hospital -- where the routine X-ray, which I saw too, revealed the "well-defined mass" hovering in his ghostly lung. I had been with him in the emergency room while the kidney stone did its work and, over the next four months, while pain and his terminal illness and ultimately the morphine emptied him of himself. Even love, given or received, could not slice through the narcotic haze of pain or the staggering awareness of our own hopelessly mechanistic mortality. This will crush even the most positive of temperaments, the fiercest of wills.

Diagnostic images of my organs glowed on the walls. I got out of the viewing room and the hospital as fast as I could.

Three days later, the stone moved. I had been waiting for it. I had told myself that that tiny rock would not do to me what it had done earlier, that I would keep the upper hand and, in so doing, keep my conscience from seeping away. But before the pain medication kicked in, the pain scattered my mind, and all things but the pain became mere suggestions of themselves. The pain reduced me to a single inflamed nerve and little more. After it was gone, my self returned but an eerie feeling stayed with me. Our psychology, our spirituality, the value systems by which we live are only possible in the absence of ill health or pain. Our essence disappears into great pain, revealing all that we hold dear to be the most fragile of luxuries.