Ah, now this is more like. Whilst chapter eight does not go out and say it directly, it is clear that a chapter called External Intelligence is buttering us up for the first of our master builders: ALIEUMS. As it is, it is a relatively well balanced chapter on SETI, and the kind of arguments for other life in the Universe (reading ahead, this may well run counter to the bits which say life is remarkably unlikely in future chapters).
Anyway, the thrust of this chapter is that SETI is a noble idea, but in searching for a message they are scanning the wrong bit of the electromagnetic spectrum. Or indeed, looking in the wrong place. After all if we have proven that the moon is almost certainly artificial (did we : oh, well) then surely its existence is a message. Maybe a somewhat cryptic message, but any message where cheese is a major component must be coming from a superior intelligence. Unfortunately in their hectoring “never use just good arguments when bad ones suffice too” way, the chapter proves the moon is a message, and furthermore the kind of message it is – having been left 4.6 million years ago for us. Surely the writing is under all the space dust:
1: The moon is designed to be meaningful only to intelligent creatures living on the Earth surface
2: It is designed to be noticed at this particular point in time (give or take a million years) because the moon only behaves in the way it does at this time
3: It appears to be addressed to a species with ten fingers because the ratio relationship of that between the Moon and the Sun is such a round number when expressed in base ten.
(One of these statements is not like the other, one of these statements is out on its own. And this is arguing a lot for a ratio of 400 which would be much more impressive if we used base 20.)
You just sense craziness around the corner.