Blue - thanks for that. I was struggling to formulate this error, but you have done it perfectly. AB assumes that evolution has a goal, and the goal is humans. This in itself produces a circular argument, since goals are always intelligent, which is what AB is trying to show.
Once he assumes that humans are the goal, then he can describe various improbabilities.
It is a bit like the deck of cards. If I am dealt 13 spades in a bridge game, I can marvel at the improbability, but as we know, if you deal out four hands of cards, each hand is improbable, and each hand actually occurs, but not as a goal.
Similarly, my own birth is very improbable, if you compute all the generations which led up to me, but of course, I was not the goal, but the (accidental) end-point!
Just to add that AB conceals this idea of a goal, typical of his dishonest arguments.