In article , Eric Flesch
writes:

On Sun, 01 Jul 12, Phillip Helbig wrote:
How probable is it that the Moon and the Sun have the same angular size?

Possibly close to 1, due to the anthropic principle: such a moon may
have been needed to give the Earth tectonic and rotational stability
across epochs, else we wouldn't have evolved to be discussing it.

Isaac Asimov pointed out in an essay called "The Triumph of the Moon"
(collected in the book THE TRAGEDY OF THE MOON, which contains an essay
by the same name) that the fact that the Moon is large in relation to
the Earth (compared to the ratios for other planets and moons) might
have an anthropic explanation. However, this cannot explain the nearly
perfect coincidence in size. (Also consider that, since the Moon is
moving away from the Earth, the coincidence holds only for a relatively
short time during the history of the Earth.)