; Date: February 16, 2020
The theory goes that because The Ruth-Doctor barely recognizes the Sonic Screwdriver, or doesn't recognize it at all, that The Ruth-Doctor must be very early. It was Patrick Troughton's Doctor that invented the Sonic. Since televised Doctor Who showed us the regeneration from Hartnell to Troughton, that means the BBC cannot insert a Doctor incarnation between the two. And therefore The Ruth-Doctor must predate William Hartnell's Doctor.
To further strengthen that theory, The Ruth-Doctor's TARDIS interior is similar in style to the early TARDIS interiors. Almost as if the show runner wanted us to associate her with the early Doctor incarnations.
The common reason why this cannot be is the exterior of The Ruth-Doctor's exterior. Namely, the Canon that has passed down for almost 60 years of Doctor Who history is that The Doctor stole a TARDIS, and escaped Gallifrey with his Grand-Daughter, landing in 1963 London. The TARDIS chose to look like a London Police Box, and then it stuck with that exterior shape, and over the next 60 years fans have become accustomed to saying that TARDIS's must look like London Police Box's.
But TARDIS's have a Chameleon Circuit, that lets them appear in any shape required to fit into the locale so that a TARDIS can be incognito wherever it goes. It's just that The Doctor's TARDIS has a broken Chameleon Circuit, or has otherwise chosen to stick with the police box shape, and The Doctor never gets around to fixing it.
It was Hartnell's Doctor that stole that TARDIS and flew to London, which is what we saw in televised Doctor Who. Therefore, if The Ruth-Doctor predates Hartnell's Doctor, then how would her TARDIS be in the shape of a police box? The Doctor's TARDIS didn't choose that shape until it (?she?) landed in 1963 London.
That rationale has some weight to it, but there is a bigger reason.
As fans the BBC has given us almost 60 years in which it repeatedly claimed that Hartnell's Doctor was the first incarnation of The Doctor.
Television shows and comic books and the like routinely rewrite the history of the show. For example with the launch of New Who, we were told there was a big nasty Time War and that The Doctor ended the Time War by destroying both Gallifrey and the Daleks. But then the BBC showed us The Day of the Doctor in which they rewrote the whole Time War narrative, and instead of destroying Gallifrey the Doctor instead pulled a fast one on everyone and pushed Gallifrey into an alternate universe. The Daleks were too busy shooting that they ended up destroying Dalek ships, and nobody noticed that Gallifrey wasn't actually destroyed.
That's a big massive rewrite of what we'd been told, and we're now to believe a different story.
As the video below says - a TV show can get away with rewriting 5 years of history, maybe 10 years of history. But in the case of Doctor Who, we have nearly 60 years during which we've been repeatedly told the ordering of incarnations of The Doctor. See Smith was 13, Capaldi 14, Whittaker 15, how many regenerations does The Doctor have remaining?
The BBC would have a very difficult time getting us to accept a rewrite of information that we've been told for almost 60 years.