None of these properties have values set, as far as we know, by fundamental laws
of nature, and quite moderate alterations produce imagined universes with
substantially less complexity than our own |=| universes where galaxies, stars,
planets, molecules, atoms or even nuclei cannot exist. Life is, if nothing else,
complexity|-|unmatched and it stretches credulity to suggest that universes that
can't even make atoms could somehow generate life. It's conceivable that the
values of physical constants in our Universe are the only possible, but the
alternative explanation, that multiple universes are actually realised in nature
and that we necessarily live in one of the few where the constants are \quote
{just right}, is surely a fascinating idea worth pursuing.
