# In an infinite multiverse, why is there only one Dark Dimension/Mirror Dimension?

So, I was watching Doctor Strange (2016) (cracking film, by the way) and I realised something odd.

The Ancient One says during an early section, before Strange's training properly starts, that believing in an infinite multiverse also means believing in infinite dangers or something close.

Later on in the film we of course meet the Dark Dimension. It's the Dark Dimension - only one, or so it's implied. But surely, in an infinite multiverse, there will be at least one, if not an infinite number of dimensions/universes in which everything is almost exactly the same, with only small differences, for example the sky is a slightly different colour. Something negligible. So why is there only one Dark Dimension? (For that matter the same thing happens with the Mirror Dimension.)

• Plus, infinite copies of infinite dimensions would be a different order of infinity. Mar 20, 2017 at 20:52
• @Gallifreyan I think Callack means there are infinite numbers between 0 and 1. So there are also a (smaller) infinite number of numbers between 0.506 and 0.507: I.e. more or less 0.506. So if in this analogy 0.506 is the dark dimension there should be infinite universes which as as like the dark dimension as to make no difference Mar 20, 2017 at 21:07
• Perhaps dimensions and universes are not the same thing. Also, perhaps there actually isn’t an infinite multiverse. This ain’t The Flash! Mar 20, 2017 at 23:28
• @Seeds, taking a cross product doesn't increase the order of an infinite set. You have to take a power set to do that. Mar 21, 2017 at 2:35
• IMO, saying "The" Dark Dimension just means "the particular Dark Dimension that is currently a threat to us". It's like when you talk about "the enemy" you don't necessarily mean they're the only enemy, just the one you're fighting right now. Mar 21, 2017 at 2:38

In my opinion, it's because universes and dimensions are different: universes are about size, while dimensions are about composition.

Think of a universe as a painting: you can have an infinite number of paintings, all of which are unique; however, they are all 3-dimensional, and every dimension is the same for each of them - what makes a painting different is not more dimensions but its presence or value in each of the dimensions in which it is expressed.

That way, the dark dimension can be infinitely large (every universe can have a dark dimension "value") and yet unique. It also ties in with how it's "invading" our dimension: universes that before had no dark presence now have one and have less "light" presence. The mirror dimension might work similarly.

• This was actually the answer I thought of just as I posted a question. To me it makes the most sense in context so I'm marking it right. Thanks for answering all. Mar 23, 2017 at 17:31

Infinite universes is not the same as every possible universe existing in every possible variation. There are infinite real numbers, but only one of those is zero, and none of them are the square root of -1.

• But an infinite number are almost zero; e.g. 0.00000001 Mar 20, 2017 at 21:15
• @user20310 - But none of them are almost sqrt(-1). ;) But if you prefer, think of the positive integers, which are also infinite in cardinality, but all at least 1 unit away from zero. Mar 20, 2017 at 21:16
• Which raises the natural question of whether the multiverse is countable. Mar 20, 2017 at 23:51
• @eyeballfrog: Not sure it's relevent. If if it is uncountable, they might all still differ from eachother by "at least 1 unit", and then this point stands. Mar 21, 2017 at 0:00
• @eyeballfrog If you add up all the countable infinite universes you get -1/12.
– Ber
Mar 21, 2017 at 1:32

## Because it's probably the only dark dimension they know about and they have to call it something.

In a universe with an infinite number of dimensions and an infinite number of possible dark dimensions, there is still only one Dark Dimension. The Dark Dimension is the name given to the single dimension containing Dormammu. The name may describe its properties and may be vague enough to match any number of other dimensions, but it's still just the name given to a single unique one.

I'd imagine it's the only dimension of its kind known to The Ancient One, otherwise it'd probably be known by a more descriptive name.

• If there were more than one with those properties, they would probably be called Dormammu's Dark Dimension, Dirmemma's Dark Dimension, Bongaggu's Dark Dimension etc. Presumably, Dormammu is unique being, because it both a being and dimension. I assume like you do, that it is an issue of naming. First time you see something, it needs to get named. Like ancient Egyptian name for cat was mau. First sorcerer supreme: What are you? Dormammu: Dormammu? ("what did you say?" in ancient language of Dark Dimension) First sorcerer supreme: Dormammu it is. Sep 3, 2021 at 7:28

There’s more than one Dark Dimension in the multiverse.

surely, in an infinite multiverse, there will be at least one, if not an infinite number of dimensions/universes in which everything is almost exactly the same, with only small differences, for example the sky is a slightly different colour

Maybe, maybe not. We have a limited understanding of the rules the MCU multiverse operates under, and I'm sure the writers don't want to invent them until they come to actually write stories that depend on them.

One such story that features "the" Dark Dimension is What If... Doctor Strange Lost His Heart Instead of His Hands? This features an alternate universe, where Doctor Strange does some... inadvisable things with the Time Stone. We see the Doctor Strange of this universe confront and defeat Dormammu in the Dark Dimension, much as our Doctor Strange did in his movie.

As such, presumably both the regular MCU, and the alternate universe portrayed in this episode, each have their own version of the Dark Dimension, as we didn't see two Doctors Strange in there bargaining Dormammu right in his big ugly face.

• The Dark Dimension is "A world beyond time". So, Strange appears at the same time or not to Dormammu and so Dormammu should notice this. If it was the same across them all I'd note we'd probably see an indication of that but we don't. Sep 2, 2021 at 15:03