Last year I was invited to give a lecture on critical thinking to the U.S. Navy. I opened my presentation with a story I’d read in Reader’s Digest magazine as a child. It’s an old story you may have heard before, but it’s a perfect introduction to the importance of critical thinking. Here’s how it goes:

A newlywed husband observing his wife preparing a roast beef was shocked to see her slice an inch off the end of the meat and toss it in the trash. “Why did you do that?” he asked. She shrugged and replied, “I don’t know; it’s what my mother always did.” Baffled that anyone would waste good meat, and curious to learn the answer, he phoned his mother-in-law and put the question to her. Her response was the same as her daughter's, “It’s the way my mother did it.” Knowing his wife’s grandmother was still alive, he phoned her next. Upon hearing the question, the older woman laughed, “Oh my, I don’t do that anymore. When I was younger and poorer, I only had one pan and a roast wouldn’t fit in it unless I cut the end off.”

 …