A couple of years ago I switched doctors. The doctor I had been seeing for years, but had never really been comfortable with, was in his late fifties and my new doctor was a young woman who was building a new practice. At the time I joked to my friends that I left my old doctor because he practiced old medicine and I wanted 21st century medicine.

Turns out, my off-hand joke contained quite a lot of truth. My young doctor is so much better that I wondered if my ‘old medicine' concept fit with other occupations as well. Don't most people learn in their twenties and thirties, practice in their forties and become set in their ways in their fifties? For someone who has done the same job for thirty years is there anything more annoying than someone half their age who knows a better way?

I think it's the daily grind of life that promotes lazy thinking. Even bright minds are dulled by experience. Familiar routines are easy. Opinions, once thought out, are held tightly regardless of new and contradictory information. Like the junk that clutters my garage, once useful knowledge, needs to be occasionally examined, tidied up or thrown away. Nowhere is this more obvious than in science, technology, and medicine.