We all become attached to our strongly held beliefs, and must constantly struggle to be open to new ideas. I sometimes find it useful to ask myself “what would it take to convince me that a strongly-held belief is wrong?” Using more scientific terminology the question becomes “How would I falsify this claim?" A famous example reportedly comes from biologist J.B.S. Haldane. When asked what it would take to convinced him that the theory of evolution is false, he answered “A rabbit from the Precambrian.”
This question has lead to some interesting discussions with friends over the years. It’s also a useful question to ask a debate opponent when discussing a particular idea. For example, if you ask “what would it take to convince you that the earth is billions of years old?”, and they answer that no evidence would convince them, you might as well end the debate. Their position is based on ideology and not reason, and no amount of evidence will change their mind.
Someone once presented me with a “what would it take” question that I still have not been able to answer. The question was “can you imagine a piece of evidence that would convince you that plate tectonics is false”? This one has me stumped. Plate tectonics so completely explains all the observed data that I simply cannot think of a piece of evidence or a competing theory that would convince me that it’s not happening. This doesn’t mean it couldn’t happen some day, but the evidence would have to be overwhelming. Sort of like the Precambrian rabbit.