Solution

(Our luncheon discussion continued.)

"That brings us back to the original question: How could we solve the problem?" I asked.

"Em...  For some of the contributing factors, we could do something about. For the others, the situation is rather hopeless." PW said.

"That doesn't sound very promising," I said to myself. If there are two dozens of causative factors and each contributes to 3 or 4 percent of the problem, it is an impossible mission to tackle each and every of these factors, while rectifying just a few would have no appreciable effect. Moreover, there could well be another dozen of causes that have not been identified.

********************
I was still pondering that problem the next morning. As some of you may know, I have a habit of reading medical textbook for half an hour each morning before doing anything else. On this occasion, I was reading the pathogenesis of hypertension.

And, all of a sudden, I saw light.