I got curious whether the Wikipedia article for Bayes’ theorem was burdened by LessWrong spam. I don’t see overt indications of that, but even so, I’m not too impressed.

For example:

P(B|A) is also a conditional probability: the probability of event B occurring given that A  is true. It can also be interpreted as the likelihood of A given a fixed B because P(B|A) = L(A|B).

The line about “likelihood” doesn’t explain anything. It just throws in a new word, which is confusing because the new word sounds like it should be synonymous with “probability”, and then adds a new notation, which is just the old notation but backwards.

P(A) and P(B) are the probabilities of observing A and B respectively without any given conditions; they are known as the prior probability and marginal probability.

But both P(A) and P(B) are marginal probabilities; they’re the marginals of the joint probability P(A,B).

The first citation is to one random guy’s book that’s just his presentation of his own “subjective logic” theory. And that reference was originally added to the article by (no prizes for guessing) the author himself, writing a whole section about his own work!

There are long stretches without citations, which I’ve been given to understand is frowned upon. On the other hand, one of the citations that does exist is to a random tutoring-help website whose “about us” page crashed Firefox on my phone. (I have been trying other browsers on my laptop, but not on mobile yet, due to finiteness of brain energy.)