Brain teaser. Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?
- A: Yes
- B: No
- C: Cannot be determined
The answer is A. If you thought C, join the club. Not only did I make the same mistake. So do most folk. According to Dave Robson, author of The Intelligence Trap:
Many Ivy League students got this wrong, and when I published this test in New Scientist magazine, we had an unprecedented number of letters saying the answer was a mistake.
When Guardian puzzle-setter Alex Bellos ran the puzzle in 2016, he got these returns.
- A 27.68 per cent
- B 4.55 per cent
- C 67.77 per cent
But A really is the answer, and here’s why. Married Jack looks at Anne. If Anne is unmarried, we have our answer. And if Anne is married? Well who is she looking at?
The logical certainty hinges on marriage being what computer programmers and other binary thinkers call a Boolean. We can apply a True/False test to derive either of two states. If “status married” is false, then “status unmarried” is true, and vice versa. Like dead or alive and – this used not to be controversial 1 – male or female, marital status knows only two states.
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- In a post back in June 2021, I wrote of a widespread idPol failure to disentangle three separate things. One, it is not OK to trash a biological male identifying as female. Two, to insist that sex is binary is not of itself so to trash. Three, regardless of whether we think sex binary or “on a spectrum”, allowing “people with penises” into space traditionally reserved for “people with vaginas” – be they changing rooms, toilets, refuges for victims of domestic violence, jails or sports events – should ring alarm bells.