I've been enjoying this series so far, and I found this article to be particularly helpful. I did have a minor suggestion. The turnstile and the logical negation symbols were called out, and I thought it might be useful to explicitly breakdown the probability distribution equation. The current Less Wrong audience had little problem with it, certainly, but if you were showing it to someone new to this for the first time, they might not be acquainted with it. I was thinking something along the lines of this from stattrek:

"Generally, statisticians use a capital letter to represent a random variable and a lower-case letter, to represent one of its values. For example,

X represents the random variable X.
P(X) represents the probability of X.
P(X = x) refers to the probability that the random variable X is equal to a particular value, denoted by x. As an example, P(X = 1) refers to the probability that the random variable X is equal to 1."

(from http://stattrek.com/probability-distributions/probability-distribution.aspx)

Also, page 2 of A Student's Guide to Maxwell's Equations does a great job of diagramming Gauss' law for electrical fields, and I think it would be helpful if this were available to breakdown the right half of the equation, with the beginning reader seeing a breakdown of the equation.

http://books.google.com/books?id=I-x1MLny6y8C&printsec=frontcover#v=onepage&q&f=false

If this all was set aside in the footnote, the overall continuity of the article wouldn't be affected, and someone who might be intimidated at first by equations might see that these aren't so bad. With just a bit of exposition, more readers might be able to follow along with the entire argument, which I think could be introduced to someone with very little background.