I came across an essay on beekeeping by Charles Martin Simon, called Principles of Beekeeping Backwards. I know nothing about beekeeping, and I initially discounted Simon's writing as Luddite crankiness (I'm all for Luddism, but I enjoy tinkering too much to believe that its ever as simple as just turning back the clock). On a closer reading, however, he describes a process that I found very familiar: the discovery that you are on the wrong path, and the realization that no amount of earnest course correction will right things. He describes realizing that everything he has learned about raising bees is in fact wrong, that he has been ignoring the signs from the bees for years, but that the deeply held principles of apiculture made it impossible to see it. He is suggesting not returning to older practices of beekeeping, but that the entire practice of raising bees for honey is founded on false principles. Its an earth-shaking idea, like realizing that if you had only been taught differently as a young child you might be flying instead of walking. We live in a world of accreted infrastructures - we are taught that the Real World is no place for idealists. It is rare that foundations are built or rebuilt from the ground up - revolutions, natural disasters, newly discovered territories. The rest of our lives we negotiate the strange minotaurs, hydras and chimaeras that we must - constantly wondering "why not" and "what if". Re-setting the game involves mobilizing so many people in the same gamble, in giving up a system that mostly works for the possibility of one that works a little better that it takes an extreme catalyst to make it happen.
Simon's sentiment reminds me a bit of Brian Eno and Peter Schmidt's Oblique Strategies - a place to look when nothing else seems to be working. A more scientific version of this might be the study of cognitive bias, all of the built-in cultural and psychological blind spots through which we see (or don't see) the world every day. One could probably cross-reference a list of known cognitive biases to the Oblique Strategies quite easily.
I believe that the most difficult and most valuable skill to cultivate as a designer is the ability to step outside your project, outside of everything you know and believe about design, and really see what you've made. It's an impossible task, of course. We spend so much time in the planning and design process building a scaffolding of confidence, trusting that our practice will create solid ground under our feet in the end.