Kathy Sierra’s site, Creating Passionate Users has a nice piece about the longevity of assumptions and how to refresh, challenge and get rid of them when they limit ideas and imagination.

The really big problem is the assumptions which are so ingrained that we don’t even know they’re assumptions. They become an accepted Law of Physics, as good as gravity.

It does little good to list (and date) our assumptions, if the most crucial ones–the ones that could lead to the biggest innovations and breakthroughs–never make it to the list. It’s not enough to say, “So, what are our assumptions here?” We have to ask–and keep asking–“So, what are we accepting as fact and not questioning as an assumption?” In other words, “What are our hidden assumptions? What do we believe implicitly?”