## Ultimate Boeing 747 gambit

The "Ultimate Boeing 747 gambit" is an argument for the improbability of the existence of God introduced by Richard Dawkins in The God Delusion. His statement (in its entirety) is as follows:

"However statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable. God is the Ultimate Boeing 747."

The reference to the "Boeing 747" is an allusion to Fred Hoyle who reportedly compared the random emergence of even the simplest cell to the likelihood that "a tornado sweeping through a junk-yard might assemble a Boeing 747 from the materials therein." (see eg Fred Hoyle. Hoyle was not a theist - but Dawkins is objecting to this argument being deployed theistically.)

Dawkins does not explain what he means by statistically improbable. The standard probabilistic form of the argument from design is to take some feature of the universe (X) and to argue that p(X/God) >> p(X/No_God). Obviously p(God/No_God)=0 < p(X/No_God), but this says does not address the argument for design. So Dawkins seems to be arguing:

1. If "D designed X" then, for any Background assumptions B, p(D/B) < p(X/B)

2. Hence for any B and X, if "God designed X", p(God/B)< p(X/B)

He gives no justification of (1) and consideration of an artist D who designs n paintings all but one of which are destroyed shows that (1) is not necessarily true. And this argument says nothing about a comparison of p(X/N) with p(X/G). Further publications may elucidate these questions. (The symbol / should be a vertical bar symbol.)