Hi there. Seagull again. Still not my name, but you get it.

Slightly off topic, if such a thing exists.

As a mage (though I prefer wizard because I think about what I do ) I have access to means to travel between realities. That being the case, I kinda wanna talk about multiversal cosmology. Keep in mind, this can only be subjective...but the topic is bigger and wider than you would think given how its portrayed in pop culture.

You'll see what I mean before we even get out of the basic terminology I'm gonna use to describe this.

So, a universe is a discrete reality. One world, but all of it. The whole thing as it exists in the same plane, timeline, milieu, etc, front to back. Our planet, our solar system, our galaxy, all the way up. That's a universe. We don't even agree on whethe that is finite or infinite, but it's our starting point.

A multiverse, basically speaking, is the entire cosmological make up of that universe. All its planes of power, its heavens, its hells. All of the different dimensions, worlds, realms, etc, that make up its frame of reference. In some cases, this includes things like alternate timelines, variants of the same world, stuff like that...but not always. Those can be separate universes, even in separate multiverses depending on other factors. 'Planar' travel is easiest within one's own multiverse. Its easiest to follow the paths from each to each, cross over where the veils thin, etc, because all of these are somehow connected.

The next step up is what I call a multiversal cluster. Loose groups of somehow connected multiverses that share cetain physical laws, perspectives, paradigms, whatever. Its easier to move within a cluster than between clusters, although again, what is or isn't in a cluster is totally subjective...except for the getting between them easier thing, which has been objectively assessed. We just aren't always sure what the connections are, or why they are a cluster.

The clusters can range in 'size', though all of them are effectively infinite. The size just refers to how many realities make up the cluster...which can also be infinite, but there are bigger and smaller infinities based mostly on how big the differences actually are between the constituent realities. Have I lost you yet?

It's fine, Try to keep up, nobody understands this stuff anyway.

Then you have megaclusters which are just groups of the aforementioned clusters that may only have as little as a 'theme' connecting them, like in narrative terms: “These are horror realities.” Lots of crossover, just like fictional genres. (Might be fitting, one person I know posits that literally everything written in fiction happened somewhere and folks are tapping into it subconsciously. Lovecraft believed that, kinda. As usual, I digress, though less than you think. We'll be coming back to good old racist HPL in a sec.)

Then you have what I call the omniverse. That's all of it. The whole shebang. Every reality, every single possible reality, spinning round each other, past each other, through each other, connected, unconnected, whatever. Every megacluster of clusters of multiverses of universes of worlds all the way down to the atom and lower (a lot of these are spheres, at least metaphorically, which is a subject for another time.)

Got it​?

Now we can START talking about this.

Come back tomorrow for part 2, yeah?