A while back I opined to a gathering of primary care physicians that America needs to shift some tasks now performed by physicians to non-physicians, intelligent machines and patients themselves. Instead of seeing a doctor, see a nurse practitioner. Ask a diagnostic computer. Diagnose and treat yourself — safely and effectively — with the assistance of new technologies.

This, I argued, is how we ultimately provide better health for more people at lower cost. One doctor was highly incensed by my suggestions. She insisted that we need greater reliance on physicians — a stronger role in guiding individual patients toward better health. My response (refined afterward with reflection) came in three parts:

First, this isn’t about replacing doctors. Rather, it’s about freeing them from mundane tasks and from caregiving that can be handled well (in some cases better) by lower-cost resources. Then, doctors can focus more on deep cognitive tasks.

Second, mathematics frustrates the doctor-as-guide vision. In America, 200,000 primary care physicians care for 320 million people. So, the average American receives well under one hour per year of primary care physician attention. In some cases, an intimate doctor-patient relationship yields enormous health value. But with 1,600 patients per doctor, such cases are relatively few in number.

Third, while my respect for physicians is vast, I suspect we greatly overestimate the importance of that doctor-patient relationship to our health. (That doesn’t justify public policies that interfere with that relationship.)

To mollify my physician-critic, I told my own history. In a half-century of adult life, I’ve had exactly four primary care physicians — all superb. I’ve only changed doctors when I moved to new towns. I’ve had strong relationships with all four, and that has given considerable peace of mind.

Admittedly, this degree of intimacy is rather unusual. My career revolves around health care, so we share powerful interests. I’m grateful to have a bit more than the average level of attention from my physicians. It’s good for my psyche, but I’m not sure it makes an enormous difference to my health.

Why? For one thing, on those scattered occasions when I changed doctors, my care didn’t deteriorate. The new doctors knew little of me, but my charts gave them all they needed to provide superb care on day one.

I developed a classroom exercise for my graduate students — most of whom are doctors, nurses and allied health professionals. I ask whether anyone in the room has had serious surgery in the past few years. Invariably, some have. I choose one and ask a battery of questions — to which they have ready answers.

“Who performed the operation?” … “Dr. Smith.” … “Where did she study medicine?” … “Georgetown University.” … “How long had she been practicing?” … “10 or 15 years.” … “Was she highly regarded by peers and patients?” … “Yes. Great scores.” … “Why did you check all this information beforehand?” … “Because my life was in her hands.”

I then asked the same student a second series of questions: “Have you flown on a commercial aircraft recently?” … “Sure.” … “Who was the pilot?” … “I don’t know.” … “Where did he learn to fly?” … “No idea.” … “How experienced was he?” … “Haven’t the faintest idea.” … “Did you check his credentials beforehand?” … “How would I?” … “Was your life any less in his hands than in the surgeon’s hands?” … “No.” “Can you explain why you were more diligent with the surgeon than with the pilot?” … “(Shrug.)”

Students struggle to explain the differences between the surgeon and the pilot. Most of their explanations crumble on inspection. Both scenarios engage in complex, delicate, life-and-death procedures. Only once have I received a truly unassailable answer as to the difference. A nurse said, “Because the pilot never asks you to take your clothes off.”

I think her answer was profound. Perhaps the real value in the doctor-patient relationship is, as the nurse suggested, comfort in a deeply discomfiting situation. That’s not trivial, but it has very different ramifications than the notion that my doctor’s intimate knowledge of me has a huge impact on my health.

That explanation is also strongly relevant to the arguments raised by my physician-critic.