You asked Joshua but if you'll pardon my making a comment:
Or other universes similar to our own?
That's why it's always necessary to be clear in terminology. As for me I refuse to depart from the traditional terminology, and for me "universe" will always mean "everything that exists." Others may way to talk about multiverses and multiple universes but I'm too old for that ![]()
Why is isonomia important to us? How is it useful? How does it helps us understand nature better?
And my answer to that, from what I believe was probably Epicurus' perspective, is that many people would conclude (if they believed that this earth was the only inhabited place in the universe) that that would mean there is something "special" about us, leading directly to a likely conclusion of divine action to explain that "specialness". Taking the position that life is naturally occurring means it's likely to naturally occur in an infinite number of places (given the view that the universe is infinite in size) so those views go hand in hand.
And to the extent we're talking about isonomia as a spectrum of complexity from extremely primitive to something we would call "godlike" that also provides a general overview to why humans should not be considered to be the highest form of life in the universe, and leads us to think about what is higher, which is something that seems to be an important part of Epicurean philosophy and helps explain why we should not, in fact, generally be satisfied with living in a cave on bread and water.