Back in the days of Uri Geller and Jean Dixon (look them up), I once told my science classes that I was able to predict the future. Of course, none of them believed me. "You had to have special powers of some kind in order to do that" they told me. They then gave me a long dissertation about Nostradamus, who was back in the news for one of his 400 year old wishy washy statements,
I created a lesson about critical thinking, and it took almost the entire year to complete. At the beginning of the year, we talked about people that said they could predict the future. We discussed what percentage of predictions needed to come true in order for them to be convinced that someone had true "psychic" skills. They all agreed that 75% was a pretty good indicator that someone had the ability to predict the future.
So I set up a demonstration: I told them that I would be able to predict the future with at least 75% accuracy. I made a set of predictions, sealed them in an envelope, even sealed the envelope with wax, and put it on a shelf, not to be disturbed until the last week of school.
When the last week of school arrived, I took the envelope down and read my predictions. Amazingly enough, I was closer to 90% accurate! The students all believed that I had some kind of power, until I explained how I did it:
I remember my father telling me that if you make enough predictions, just by chance, some of them will come true. Psychics, because of the full time scam that they practice, all they do is make predictions. Sheer volume would indicate that they have a chance of making a prediction come true. JFK will be assassinated. JFK won't be assassinated. Either way, the psychic will be right and you will only hear about the prediction that came true.
So, I set about making my "predictions." Some would be pretty obvious based on statistics and patterns that I had observed over the years. For instance I knew the local university football team had not had a winning season in decades, and that trend was not going to change this year: Prediction 1: UTEP football will have a losing season. Easy. The basketball team, on the other hand, was pretty good, stacked the early games of the season with patsies, and almost always had a winning season. Prediction 2: UTEP Basketball will have a winning season.
Large snow storms come to the desert rarely, but light snow is very common in the winter, even if it only hangs around for a few hours at a time. Prediction 3: It will snow in El Paso this year. (Notice the ambiguity of that phrase. I didn't predict amounts, only that it would snow.)
And on and on it went until I had about 25 predictions: A famous movie actor will die. A politician will be involved in a scandal. A plane will crash in a foreign country. A famous rock star will be arrested. The price of gasoline will go up.
With those types of predictions, I got close to what I thought would be 75% , but I knew I had to hedge some bets, so I made some predictions that I would be be pretty sure I got correct:
The stock market will go up 10 % The stock market will NOT go up 10%.
A politician will be assassinated (I did that one because of all the psychics that say they predicted the JFK killing.) A politician will not be assassinated.
And on and on it went. My 25 initial predictions became 100 by the time I finished them, sealed the envelope and in front of the students, placed it on top of a large glassware shelf, where it sat for the rest of the school year, until I took it down the last week of school.
Most of the kids had forgotten about the envelope, but quickly remembered when I took it down. I had a student examine the seal to make sure it had not been tampered with. Another student opened the envelope up, to make sure I was not able to slip in a new set of predictions.
When I read them to the class, they were amazed at my abilities. Surely, Mr, Holt had some kind of mystical powers. In fact, I explained to them, I had the power of noticing trends, statistics, hedging bets, and using language to make ambiguous statements that could be interpreted many different ways.
By the end of the lesson, the students saw how predictions were made and how "psychics" were nothing more than flam flam artists out to make money off of unsuspecting rubes.
I thought about that lesson recently, and thought maybe some of you could replicate it in your classes, when explaining how to think critically about something.
I predict you will use this idea in your classes. Or you won't.
Either way, I am correct.