How do we know…

Wow! I read terrific post on Pharyngula yesterday that I just want to share.  In Dear Emma B. Myers takes issue with a somewhat canned question asked by a 9-year-old girl about the age of objects, in this case a 3.75 billion year old moon rock.

Emma asks a museum docent “Were you there?” after looking at a moon rock display. Emma has clearly been coached to ask this question because it’s an obvious “gotcha!” This isn’t a question so much as a statement of belief that we can’t possibly know ‘because we weren’t there’. There are a great many events in human history alone that none of us were present for. How can I know they happened? Because there is evidence that they happened. Imagine if you only believed things that happened while you were present. How can we know about the civil war? Ancient cultures? How about dinosaurs? How can we know they even existed if humans weren’t there to see them? (Yes I realize that the same people who fed this non question to Emma also believe that dinosaurs and humans co-existed). The point is, none of us were there so by this logic we simply can’t know. No one really believes this right? It’s a ploy and a cheap one at that.

Myers writes a fabulous letter that will never be sent to Emma, explaining why a better question would have been “How do you know that?”

You could have asked the lady at the exhibit, “How do you know that moon rock is 3.75 billion years old?”, and she would have explained it to you. Maybe you would disagree with her; maybe you’d think there’s a better answer; maybe you’d still want to believe Ken Ham, who is not a scientist; but the important thing is that you’d have learned why she thought the rock was that old, and why scientists have said that it is that old, and how they worked out the age, even if they weren’t there. And you’d be a little bit more knowledgeable today.

He then goes on to explain radiometric dating in a way a young child can easily understand.

One way to think of it is that it’s like an hourglass. You know how they work: you start with all the sand in the top half of the hourglass, and it slowly trickles into the bottom half. If you see an hourglass with all the sand at the top and none at the bottom, you know it was recently flipped over. If you see one with half the sand in the top, and half in the bottom, you know it’s about halfway through the time it will run. And if you look at how quickly the sand moves through the neck of the hourglass, you could even figure out how long until it all runs out.

Read the entire letter. Really, it’s worth 5 minutes of your day. So far, my kids accept the fact the Earth is 4.5 billion years ago. They’ve never asked “how do I know that?” Perhaps our studies have been just that convincing!  It seems more likely it just never occurred to EJ to ask and if so, then I have been remiss. As a secular home educator it’s important to me that my kids understand and think about what they are learning and not just accept what I or anyone else tells them as unquestionable fact. But, they need to have the mental tools to think critically so as to not be tricked by this kind of  “gotcha!” question. Even better would be for someone they know to ask them “how do you know that?” and being able to answer the question.

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2 responses to “How do we know…

  1. Wonderful post. Thanks for the link and thanks for pointing out how critical thinking skills insulate us against “gotcha” questions.

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