Last winter in a subway station in Shanghai I fell flat on my face.

Young Chinese commuters pulled me to my feet. After a few minutes of adjusting the bent frames of my glasses, I re-entered the surging crowd. But I felt strange and vulnerable, and shaken, as if the wings of old age had beaten briefly around my head and ears, and then flown on.

My right leg had been dragging a bit for months, and it felt heavy when I lifted it over the street curbs. Not long after the fall, I noticed my fingertips were numb (though not my thumbs, oddly). And my right hand became slow and less dexterous than my left. Typing was painful and clumsy. I knew something was wrong, but could not be sure which of the serious (or utterly devastating) causes — so easily researched on the Web — it could be.

Our children visited Shanghai in late May. On the sidewalks they saw how unbalanced my walking had become. Sometimes I found I was clenching my fists as I concentrated to avoid swerving too much from side to side. My father years ago in very old age said, “I am sorry you have to see me this way.” I remembered his words, and relaxed my hands on purpose, so the children wouldn’t think I couldn’t control them better than my legs.

“I will see a doctor as soon as we are back in New York in June,” I promised.

Within days of arriving in New York, I had been examined, tested, imaged, and scheduled for urgent surgery at an exceptional hospital. I am fortunate in so many ways. To have the wherewithal and insurance to afford fine doctors, and to live in a country that has such noble traditions and institutions of medicine. And rather than some incurable condition, it turns out that the source of my lack of coordination was a severe compression of the spinal cord in my neck. It could be treated. The only reasonable course of action, all the doctors agreed, was to have a serious, but fairly common, operation.

I had about ten days between the diagnosis and my surgery date, and during that time I took many slow walks though Central Park. I wore a white neck brace, which made me feel marked and separate, as much as if I had worn a priest’s collar.

In my state of worry and weakness, I noticed how many people around me also walked with difficulty, and how many struggled to get on and off the “kneeling” cross-town bus. I especially watched the toddlers testing the earth with their trembling legs. I took note as I had seldom done of all the lame and the infirm, who are legion, and now I felt I was one of their number. I wondered about their medical care and insurance, not doubting that for most of them it was a far cry from my own.

And I thought back to college philosophy and the lucid Cartesian attempt to separate mind from body, and I knew in my bones it was wrong: our minds are created by our bodies and depend utterly upon them. But I also experienced the Cartesian sensation of being a ghost inside a machine: needing to consciously direct my limbs to move, and observing them as I might observe the movements of a robot.

When I flexed my fingers and rued their loss of natural sensation and innate capability, I thought, as the lonely philosopher Wittgenstein had remarked, that no one else can know what I feel. Just as I cannot be sure I understand what they feel. Is my neighbor on the bus also suffering from numb or weak fingers, or a numb heart, and how would I know? Only through language, I suppose, from talking to each other.

But what of my private remembered sensations? Have my hands always felt this way? There is no one to talk to about that. No certain language. Yet I know these hands once felt more alive than now.

Well, the operation was six weeks ago, a daily routine for the neurosurgeons but a miracle for me. It went well, the doctors said. I am now learning again to walk as most others do. I am again able to type with all my fingers without thinking about it too much. It no longer hurts to write.

So if you see me this summer, along one of the roads from Rockport to Camden — striding with a hint of a limp, but still resolved to put one foot in front of the other for at least the next mile or so — don’t see me as just a man walking.

For me, these days, all walking is dancing.