It's silly to say something like "A non mathematical introduction to this mathematical concept". What the author really means is that he's not using equations in his introduction. Far too many people think equations are what mathematics is solely about, and titles like this perpetuate that stereotype.
This post would have been better if it actually used equations. A few short equations are easier to understand that a bunch of lengthy paragraphs. In fact P(A|B) = P(B|A)P(A)/P(B) is compact and not hard to understand, but there are entire books written about it!
I agree that equations should have been introduced, but I disagree that your example is not hard to understand, which is the point. I'd rather read about the concepts than look at esoteric equations.
It's silly to say something like "Far too many people think equations are what mathematics is solely about". What you really mean is that far too many people think series of statements containing numbers and variables are what mathematics is solely about, and comments like this perpetuate that stereotype (ie. all math statements containing numbers and variables are equations)
And that's why arguing about word meanings is not a good idea. I think referring to written math as just math is reasonable, and referring to it as equations also is.
