Translation: This is the anthropic principle applied to the direction of time.

Basically, he's saying that universes which have a definite direction of time are much more likely to be very large and long-lasting, and have many more opportunities for "observers" (like us, or our particles, depending on whether you've read http://www.sciencenews.org/view/generic/id/35391/title/Do_su... ) to exist, than those which do not have a definite, reliable direction of time.

And therefore, because we exist, we are much more likely to find ourselves in one of those kinds of universes than in one which is not so compatible with life.

This is probably not the most interesting article I've read on OvercomingBias... the others usually make more interesting arguments.

What's your favorite Overcoming Bias post?

This is mine: http://www.overcomingbias.com/2008/05/faster-than-ein.html

Yep, I love that one.

I also liked the recent one about the lever, don't have a link handy.

Most of them are excellent, but those two stand out for me.

What's wrong with this simpler explanation:

There are several time arrows, expansion of the universe, entropy increase, and your perception of future and the past. The last two are not independent at all, as your perception of the past is based on the memory which in turn is a chemical process that follows entropy increase. So the answer to "why things do not happen backwards in time more often" is that because your perception of direction of time is always aligned with the entropy increase.

Yeah, didn't Hawking write about cosmological versus thermodynamic versus perceptual arrows of time, in A Brief History of Time, like 20+ years ago? (Therefore I assume it was well-established even before that).

Plus, I may be missing something, but what's the difference between the self-indexical principle and the anthropic principle?

I understand it that self-indication is for any observer, not just us puny humans. Oh, and that might be the answer to my question too!

I'd heard that idea about the likelihood of living in the most populous time in history (which is depressing), and that extends nicely to observers of the universe.

What's depressing about it? There have never been more <Put your favorite kind of people here.> around.

It implies imminent human extinction.

Why? At nearly all times in history there have been more people on earth than ever before.