A slight change of direction this month: this entry is named after a non-mathematician who is the subject of the thing rather than the discoverer.
You might have heard of the subject.
What is Nixon’s diamond?
Nixon’s diamond is a logical scenario that seems to be a contradiction. The canonical example uses a former president:
- Quakers are usually pacifists, and Richard Nixon was a Quaker – so Richard Nixon was likely a pacifist.
- Republicans are rarely pacifists, and Richard Nixon was a Republican – so Richard Nixon was likely not a pacifist.
Good golly! He can’t be likely both, can he?
Why is it interesting?
I think it’s interesting because it exposes the limits of modifiers like “usually”. The apparent paradox is easy enough to resolve mathematically (given probabilities of Quaker pacifism, Republican pacifism, and the dependence of one on the other, we can figure out the probability that a randomly chosen Quaker Republican is pacifist).
Who was Richard Milhous Nixon?
He was the 37th President of the USA, and the only one (so far) to resign his office. I have three interesting things about him:
- He resigned the day my parents got married and my partner was born
- Dick Dastardly’s middle name is also Milhous
- Hunter S Thompson described him as “so crooked that he needed servants to help him screw his pants on”.
He was born in California in 1913 and died in New York in 1994.
A selection of other posts
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