Despite the woo-woo nonsense that often gets associated with metaphysics in the popular press, (astrology, as an example, does have its own odd sort of metaphysics...) in point of fact coming up with a functioning metaphysical theory of the universe is a key starting point in all scientific activities. To actually do science, to systematically explore variation and make reliable predictions about the future, you need something in which to ground your work. Some idea of what the world is made of, and how it came to be.
At present, the vast majority of scientists agree that our reality is comprised of a set of fundamental particles, which have certain characteristics that cause them to interact with one another in a predictable way. They also agree that there's a powerful force (gravity) that has detectable effects on those fundamental particles, especially when there's a lot of them clumped together. But, so far, no one has been able to come up with a unified perspective that can account for both these aspects of reality in the same model of reality. That is, although we have strong empirical evidence that gravity is real, and also that quantum mechanical effects on particles are real, we still have no idea how to make these two aspects of reality play nice with one another in the same set of basic equations. We just know that if you are trying to understand big stuff, like the movement of stars, planets, and galaxies, you generally want to use gravitational theory to predict their behavior. And if you are looking at little stuff, atomic and subatomic particles and fundamental forces, you invoke the strangeness that is quantum mechanics to try and understand what is happening.
One of the greatest ambitions of most physicists is to come up with a unified theory that integrates gravity and quantum mechanics to produce a comprehensive theory (and, ultimately, metaphysics) of how our reality came to be, how it works, and its future evolution. But so far, all that can be said with any confidence is that at the beginning of our universe, all the matter that is now spread across billions of light years was clumped together in a super-hot, tiny space. And, for some reason, a “Big Bang” occurred, resulting in the expansion of our cosmos to its present configuration over the course of nearly fifteen billion years. An expansion that is ongoing and apparently even accelerating, for reasons unknown and with uncertain consequences in the long term (I mean really long term: many billions, perhaps even trillions, more years).
Now, mythology is also deeply concerned with the questions of what the world is made of, and how it came to be. Metaphysics and mythology are deeply intertwined. In a very real way, the metaphysics contained in many mythological traditions represent humanity's first draft of what was to become science, just as they contain the first version of what we call history. So, in Bringing Ragnarok, I “solve” the problem of making gravity and quantum mechanics play nice by proposing that each originates from a different universe, and that the overlap of several independent universes, three of the Nine Worlds of Norse Mythology: Niflheim (mist-home), Muspelheim (fire-home), and Jotunheim (giant home), caused what we call the Big Bang. Niflheim is, in my metaphysics, the source of gravity, Muspelheim the source of matter/energy, and Jotunheim the source of the attributes of matter that produce quantum effects.
And then, I add another twist: many physicists are beginning to accept the view that our universe is one of many, and that different universes were also born at the same time as the Big Bang, each potentially “evolving” a little differently than all the others. Now, in several versions of Indo-European mythology, there's this concept of reality being something like a net or web, with different realities being represented by different branches. So for Bringing Ragnarok, I merge the idea of the multiverse with the Norse concept of the Web of Norns.
In the Norse myths, the Web of Norns is spun by three mysterious deity-like figures, who weave into it the fates of all those living in Midgard (and maybe beyond). My author's conceit here is to make the Web of Norns something more technological in nature: rather than there being three women who choose people's fates (they're more operators than drivers, so to speak), instead the Web is a visual representation of the multiverse itself, with each independent reality appearing as a golden Thread that is adjacent to and sometimes even merges with other Threads. The Norns are basically sampling the realities they can access, and using a sort of metaphysical statistics to predict the past, present, and future of all Threads.
This is how the Norns appear to know the fate of people living in Midgard: they are able to look at similar Threads and evaluate events. And this is how the Six Friends of the Saga are able (once they learn the ropes) to predict what actions they need to take in their different Threads to try and alter the course of events.
This metaphysical setup also lends itself quite well to the apocalyptic theme I'm (heh – weaving) into the story. Because, as most anyone with a passing familiarity with Norse mythology probably remembers, all realities are fated to end in Ragnarok. Midgard and all the neighboring realms alike. Because once they were bound together at the start of the Big Bang, they remained bound to one another. And eventually, because of something very particular about the way this metaphysical conceit plays out, they will eventually share the same fate: annihilation.