9 Comments
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BrotherCreamy's avatar

Wouldn’t you need to test all the cards? Because for any 3 of 4 the rule could hold, but then fourth could violate the rule.

Adam Haman's avatar

Nope. The other two don’t pertain to the rule. Doesn’t matter what’s on the other side of the 7 and doesn’t matter what’s on the other side of any non-A card.

Spreadsheet Anarchist's avatar

One of the major failing of our education system is that advanced mathematics is taught independently rather than in conjunction with physics to provide concrete use cases for trigonometry and calculus. It’s amazing this simple experiment hasn’t changed our approach to math.

Adam Haman's avatar

Totally agree.

Charles Rosa's avatar

Cool problem. I like the solution. Sounds like a design of experiment. Whats the most efficient way to determine whether the hypothesis is true

Adam Haman's avatar

It would be fun to try to do similar logic tests of varying types, and test them along a spectrum -- from very abstract to completely grounded in the day-to-day.

I think it'd be interesting to see the results.

Charles Rosa's avatar

Yes. The suggested solution is a kind of proof by contradiction almost. Assume the opposite….and try to show the opposite is true. If you can’t, then you hold onto the “null hypothesis “

Domenic C. Scarcella's avatar

The solution to the four-card test is an example of the axiom that a statement and its contrapositive have equivalent truth/falsity. "If A, then 7" equals "If not-7, then not-A." You check the truth of the original statement by turning the A to check for a 7, but also by checking the not-7 to make sure it gives you a not-A.

Adam Haman's avatar

Yup. And people know it when the situation is presented as a real thing with real consequences in the real world.

But with abstract symbols on playing cards for zero stakes? Nope.