Man, like, anthropics is hard. Sometimes, when trying to propose an anthropic argument, you end up conditioning on something that is basically what you're trying to elicit a probability of, and things get weird.
If it makes you feel better, I have a head for this stuff and I strongly suspect that what he said is complete bunk. But I'm waiting for confirmation before I make that judgment.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.