Adam Johnson doesn’t get statistics

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at:, or follow me on Twitter.

Here is bizarre post by Adam Johnson in which he tries to prove that a fictional “Mary” is more likely to be a bank teller than a bank teller and a feminist. He’s trying to make a point about sets and subsets. If his intro consisted only of the first sentence I just wrote, he would be correct. But he destroys his own argument with this intro:

She is 31 years old, single, outspoken and very bright. She studied philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Everyone I know treats “social justice” and “feminism” as close to being synonyms, so it is reasonable to read this intro as describing Mary as a feminist. So is Mary a feminist? The most reasonable interpretation of the text has already told us that Mary is a feminist, therefore there is no need to reference sets, subsets, or statistics. We can simply go with definitions and synonyms.

Adam Johnson tried to be clever and he sabotaged himself. He could have instead said “If B is a subset of A and x is an element in A, is it more likely that x is in A or in B?” Written like that, he would be on safe ground. But instead he tried to pose this as a word problem. And words have meanings. And words continue to have meanings even if you want to assert that you see some secret mathematical pattern in the words. Your words have to first make sense, before one can try to derive a function from the words. And in this case, Adam Johnson wrote a series of words that mean something quite different from what he actually wanted to say.

What’s even worse is he then tries to layer a thick slab of psychology over his mistake:

This is a Cognitive Illusion—something which the human brain instantly sees as one way, even though it’s really another way.

Actually, this is the Dunning-Kruger effect:

In the field of psychology, the Dunning–Kruger effect is a cognitive bias wherein people of low ability suffer from illusory superiority, mistakenly assessing their cognitive ability as greater than it is.

That is, Adam Johnson thought he had to skill to pull off this blog post, but he was mistaken.

Post external references

  1. 1
  2. 2