Well, first off all, it's important to note the meta, namely that this thread is largely just an excuse to show examples of characters reading/watching stories in other continuities, something I find interesting.

That having been said, evidence is not necessarily the same as proof. Characters reading/watching other fictional characters' adventures does not prove they are in separate universes but it does point in that direction and combined with other evidence can help lead to that conclusion. To use Sons of Anarchy and The Shield for example, despite certain flights of fancy, both are fairly realistic compared to superhero shows, space operas, and the like. Sons has one character who a case could be made is supernatural (the homeless woman) but otherwise both shows veer fairly close to the real world. Both shows also share a lot of the same actors. So when you add Juiice watching The Shield on TV to the mix, the most likely conclusion is that the two shows are not set in the same universe.

Also, a distinction must be made between universe and multiverse. That two characters don't share the same universe does not preclude them from sharing a multiverse. The Flash of Two Earths story is a good example of this. Barry reading about Jay's adventures was not proof that they were in the separate universes (such stuff was hardly unknown in the Golden Age even when the same Earth was involved) but it was certainly evidence pointing in that direction, particularly Barry referring to Jay as a fictional character. As it turns out the evidence proved to be correct in this instance: the two characters certainly share a multiverse, but Pre-Crisis, the Earth that Barry lived on was in a different universe than the one Jay lived on. They shared the same reality in some sense, sure, but I was careful in my wording to only refer to only sharing to the same universe.

The Doctor Who/Sherlock Holmes case is a bit of a grey area here. It could be that Doyle is subconsciously tapping into the events on another Earth. If so, ignoring other continuities, there could be three Sherlock Holmes running around on different Earths: the ones we read about, the one who exists in the Doctor Who continuity, and the one that Doctor Who characters read about, which may or may not be the same one as the one we read about. It's probably still interesting to note such examples, but include a caveat.

So just to be clear, this thread isn't about stating that characters from one show, etc cannot travel to another or tap into another in some sense, just that the evidence of characters reading/watching something points towards them not sharing the same universe.

Some relevant quotes from the Omniverse Map thread:

zuckyd1 wrote:

Seinfeld's Kramer once guested on fellow sitcom Mad About You. Yet in a later episode of Seinfeld, George talks about how he hated the show Mad About You! One inventive explanation I've heard is that, since Paul Reiser's character on Mad About You is a documentary filmmaker, what George was actually referring to was a TV documentary series Paul made about his own married life. (Give that person a No-Prize!)
Another explanation is that there are two parallel universes, one in which both Seinfeld and Mad About You "really exist" and another in which only Seinfeld is real and Mad About You is, as in our universe, merely a TV sitcom. The sitcom creators in the 2nd universe are undoubtedly subconsciously channelling actual events from the 1st universe when they create their "fictional" sitcom episodes.

Stuart V wrote:

Both are valid options. Another is that, since we have evidence of realities shifting in and out of synch with one another (see Shattered Image for one such case), the two shared a reality for a while, then went out of synch, becoming fictional to one another.

captainswift wrote:

The Seinfeld/Mad About You conundrum reminds me of the so-called "Hooterville Trilogy" of late 60s TV shows. It creates an odd shared universe situation in that:

1. Green Acres definitely shares a reality with Petticoat Junction. The regulars from Petticoat appeared frequently in the first season of Acres, and Sam Drucker was a regular on both shows simultaneously.

2. Beverly Hillbillies definitely shares a reality with Petticoat Junction. Several holiday episodes involved the Clampetts going to visit Junction, and Granny was notably smitten with Sam Drucker (which would lead one to conclude all three shows share a reality, since Sam was a regular on Acres, too. However...)

3. Beverly Hillbillies is definitely fictional on Green Acres. Eb mentions it as his favorite show several times, and once the town put on a "play" that was actually them acting out an episode of Hillbillies.

So, in conclusion... jokes are more important than continuity in Hooterville.

Stuart V wrote:

Or else the Beverly Hillbillies was the first reality TV show, and that's what Eb watches. Or the Clampetts' real life rags-to-riches story provided the basis for a fictional series, just like, for example, we have TV series based (loosely) on the real world Untouchables.

Revisiting this, with a couple of new examples and setting some ground rules for going forward:

Ground rules first. Two fictional tales, be they films, TV series, books, etc. are considered to be different universes if one of them unambiguously refers to or depicts the other as a fiction within that universe. This holds true even if they at other times cross over with one another. Yes, any such references could in theory be worked round by assuming documentaries or fictionalized accounts of true events, but since that could be applied for almost every case we'll take that option as read and set it aside for this discussion. Similarly we know realities are not shared if the two fictions are in some way obviously incompatible - for example, two different TV shows that depict the current day world suffering a worldwide and open alien invasion. The 1960s Invaders could fit alongside the 1990s War of the Worlds TV show, since both are covert invasions, but the TV shows V and Falling Skies can't, as both invasions are very public. Note that aliens being known to exist doesn't in and of itself make said show incompatible with more "reality-based" show. For example, the movie/show Alien Nation could still fit in a world normally depicted as more mundane since it's established there were only a few thousand of the alien Tektonese and they are virtually all living in the California area. So Lethal Weapon (set in LA) can't fit with Alien Nation easily, but Elementary (set mostly in NYC) could.

Lastly, a passing reference to characters from another show does not automatically make them different realities. I can't remember the specifics because I watched the episodes so long ago, but in Charmed one of the three Halliwell sisters makes a comment along the lines of "Where's Buffy when you need her?" - that's ambiguous enough that it could be her referencing a real world version of Buffy Summers she has met.

Okay, with those baselines set:
First Wave, a 1990s show about a covert alien invasion, cannot share a universe with X-Files. In the second episode a character scoffs at being told of aliens by telling the other person to "stop watching the X-Files."

zuckyd1 wrote:

Loki wrote:

in Charmed one of the three Halliwell sisters makes a comment along the lines of "Where's Buffy when you need her?" - that's ambiguous enough that it could be her referencing a real world version of Buffy Summers she has met.

The Wold Newton crowd are particularly fond of those sorts of explanation.

I know, and I can understand why - it's a perfectly reasonable way to explain such references. After all, characters who do share a universe reference one another that same way under the right circumstances. 

I have to admit that while I love the idea of characters all sharing a universe so they can interact, I've grown less fond of the Wold Newton version as time has passed. While I don't think it unreasonable revealing that all the different versions of (say) Dr. Frankenstein are actually members of a single family tree, repeating their relative's original experiment, I do balk somewhat at trying to make absolutely every exceptional adventurer, detective, larger-than-life villain, etc. ALL related to one another, nor do I like effectively erasing characters by revealing that the Shadow was also G-8 and the Spider (as Wold Newton originator Philip Jose Farmer originally posited). I feel the first is a step too far, and the second robs us of interesting characters.

Another throwaway reference, and one that doesn't 100% rule out sharing a universe, but it does suggest it. In the 2010s Roswell series (as opposed to the 1990s version), one of the aliens is worried that she might be suffering periods of mental instability, during which there is evidence that she might be using her powers to kill people. She promises another character that she won't go "Dark Willow" on them, a reference to a storyline from Buffy the Vampire Slayer. Given it is established that she's lived her entire life in New Mexico, that she would have been a child sealed in a suspended animation pod at the time when the Dark Willow storyline was set, and that in the Buffyverse the Dark Willow incident isn't public knowledge, it's hard to write that off as a reference to real events she was aware of. 

Loki wrote:

Another throwaway reference, and one that doesn't 100% rule out sharing a universe, but it does suggest it. In the 2010s Roswell series (as opposed to the 1990s version), one of the aliens is worried that she might be suffering periods of mental instability, during which there is evidence that she might be using her powers to kill people. She promises another character that she won't go "Dark Willow" on them, a reference to a storyline from Buffy the Vampire Slayer. Given it is established that she's lived her entire life in New Mexico, that she would have been a child sealed in a suspended animation pod at the time when the Dark Willow storyline was set, and that in the Buffyverse the Dark Willow incident isn't public knowledge, it's hard to write that off as a reference to real events she was aware of. 

Second season of 2010s Roswell: a character has a dog named Buffy. Another character greets it with "hello Slayer" and admits that when he was younger he had a pet named Willow. 

Loki wrote:

Isn't Sex and the City meant to be the main character's diaries now being sold as books, or something along those lines? If so, then at a stretch the mention in Girls could be referencing those books or an in-universe TV adaptation.

I found the scene in question (one swear word). Given the dialogue. while not impossible, it would be a huge stretch to say that Shoshanna was talking about a "real" Carrie. Notably, she has a clear opportunity at the start of the bit to tell Jessa that Carrie is real but instead merely clarifies that Sex and the City was a show before it was a movie. Nice touch in the scene having her think of herself as all the main SatC characters except the one she most resembles.

Andy E. Nystrom wrote:

Loki wrote:

Isn't Sex and the City meant to be the main character's diaries now being sold as books, or something along those lines? If so, then at a stretch the mention in Girls could be referencing those books or an in-universe TV adaptation.

I found the scene in question (one swear word). Given the dialogue. while not impossible, it would be a huge stretch to say that Shoshanna was talking about a "real" Carrie. Notably, she has a clear opportunity at the start of the bit to tell Jessa that Carrie is real but instead merely clarifies that Sex and the City was a show before it was a movie. Nice touch in the scene having her think of herself as all the main SatC characters except the one she most resembles.

A character not being aware that the books, TV show or movies they are fans of are based on real events is far from impossible - in Doctor Who, the Doctor himself dismissed Robin Hood as fictional and stubbornly stuck to this for a while even after meeting the man; in the real world, I've seen people genuinely surprised to learn that Titanic was based around a real ship sinking.

Loki wrote:

A character not being aware that the books, TV show or movies they are fans of are based on real events is far from impossible - in Doctor Who, the Doctor himself dismissed Robin Hood as fictional and stubbornly stuck to this for a while even after meeting the man; in the real world, I've seen people genuinely surprised to learn that Titanic was based around a real ship sinking.

A couple of things here. First off, unlike Robin Hood, Carrie and Shoshanna are both Internet Age characters. Carrie's existence as a minor celebrity would be well documented. Shoshanna, being an obvious hardcore fan and not a casual viewer would almost for sure have unearthed Carrie's wiki page at some point.

The other thing is, the thread is "Evidence of Separate Universes", not "Evidence of a Lack of Counterpart on a Particular Earth". Sex and the City, except maybe the narration was not shot documentary style, so the show, even from the perspective that Carrie the writer is real, is still a dramatization with the artistic license that entails. Except maybe for Samantha, the characters are generally not depicted as exhibitionists. So even if there is somehow a real Carrie in the world of Girls, it is most likely her counterpart that Shoshanna saw on Sex and the City and not the "real" Carrie. Just as from an Omniverse perspective, when we watch Blaze, Catch Me If You Can, The Informant!, etc., we're watching other Earth counterparts of people who exist on our Earth and not the exact versions from our own Earth, as details will differ. So "real" Carrie or not, Girls and Sex and the City almost for sure take place on different Earths given the evidence available.

This one is tricky:

In Uncanny X-Men #174, Kitty is reading a Star Wars comic. Now obviously in the Marvel Universe, Marvel publishes comics featuring "real" people. But two things have to be considered here (with the usual evidence that evidence is not confirmation). First off the events of Star Wars take place far the past and in a distant galaxy, making it less likely that the 616 Marvel would have obtained accurate records. Second, as we learned from the Goody Two-Shoes story, some at Marvel are not above embellishing "real" events. Kitty comments on the dialogue, and it's unlikely that Marvel would have recordings of actual dialogue. It therefore seems likely that either the events of Star Wars are entirely fictional on 616 or that the Star Wars comic that Kitty was reading presented a fictionalized account of the events. Just as the Hitler in the movie Downfall is not the Hitler of the "real world" despite having a very similar history.

That's partly why I think Star Wars might be entirely fictional in 616. A company that only published material based on real people, no matter how fantastic likely would have trouble staying afloat.

True (and I caught the pun), the company logo is a bit blurry. The illustration also shows Kool-Aid Man in an ad, but I consider that one a "push". The ad could just as easily be showing an fictional character as an actual advertising rep.