The fact that the oldest TV sci-fi hero can change their appearance has proven handy for longevity. Once Doctor Who introduced the concept of regeneration in 1966, any actor, of any background could, technically be the Doctor. But, within the Who canon, a Time Lord was always detectable. If Daleks and Cybermen didn’t recognize them, then the two hearts would give the Doctor away. That is, until 16 years ago. On May 26, 2007, Doctor Who dropped the episode “Human Nature,” and changed the rules of the Time Lord game forever.
Although “Human Nature,” and its concluding episode, “The Family of Blood” aired over 15 years ago, the basic concept originated in 1995, in a novel written by Paul Cornell, also called Human Nature. As a part of the Who line of books called “New Adventures,” Cornell — with input from writer Kate Orman — developed the idea of the 7th Doctor (Sylvester McCoy) transforming his DNA to become human in an effort to hide. For Season 3 of the contemporary Doctor Who, Cornell adapted his story for showrunner Russell T Davies, and delivered one of the most classic Who episodes of all time.
In 1913, just one year before the outbreak of WWI, we meet the 10th Doctor (David Tennant), teaching at an all-boys boarding school, in the guise of a teacher named “John Smith.” Martha Jones (Freema Agyeman) is working at the school as a maid, and putting up with horrible racism and sexism all in the interest of protecting the Doctor. On top of all of this, the Doctor seems to have total amnesia and doesn’t actually know who he is, save for recurrent dreams, all of which he scribbles down in a journal in the form of extravagant fiction. Bottom line: John Smith doesn’t know he’s the Doctor, and can’t know until a group of ruthless aliens called The Family of Blood stop hunting him.
Turns out, the Doctor has used ancient Time Lord tech called a “Chameleon Arch” to change his biology and store his memories in another location. In this case, the Doctor’s memories, and true identity exist in a fob watch, complete with telltale Gallifreyan markings. After the Family of Blood finds the Doctor, the jig is up, endangering not just the Doctor’s secret, but the people of 1913, too. Not only does Martha Jones have to carry most of this burden, but as John Smith, the Doctor also becomes romantically involved with the local school nurse, Joan Redfern, played memorably by Jessica Hynes. (Fun fact: In 2007, Hynes was perhaps best known as the co-creator and co-lead of the cult classic comedy, Spaced, which basically launched the careers of Simon Pegg, Nick Frost, and Edgar Wright.)
In terms of David Tennant-era Doctor Who drama, “Human Nature” is exactly the kind of story that makes this era of the series so beloved. The idea of our hero becoming doubly isolated, not just because he’s a Time Lord, but also because he’s been transformed into a human is brilliantly sad. The audience knows there’s no way the Doctor will remain human, but the emotional loss of this other version of him — a slightly kinder, gentler 10th Doctor — allows us to mourn the passing of one kind of Doctor, sans the usual regeneration. The performances throughout both parts are also top-notch. Agyeman utterly sells the idea of being a human from 2007 trapped in 1913, in a way that many time travel stories never come close to. And in addition to the understated and very grounded performances from Hynes, Thomas Brodie-Sangster — now known for Game of Thrones and The Queen’s Gambit — is perfect as young Tim, the boy destined to remember the Doctor forever.
But, just as the Chameleon Arch rewrote the DNA of the Doctor, “Human Nature” rewrote the rules of the entire series. After this episode, it suddenly became possible for other Time Lords to exist in plain sight, possibly disguised as another species. In fact, showrunner Russell T Davies essentially used “Human Nature,” as a way of setting up the Season 3 finale in 2007. In the 2007 episode “Utopia,” the Master returned in the guise of Professor Yana (Derek Jacobi), unaware he is actually a Time Lord, that is before he regenerated into John Simm.
And then, 13 years later, in the episode “Fugitive of the Judoon,” the 13th Doctor (Jodie Whittaker) encounters a woman named Grace (Jo Martin) who, as it turns out, is a previous incarnation of the Doctor, using a Chameleon Arch to hide on Earth. Throughout the rest of Jodie Whittaker’s era, the existence of the Fugitive Doctor created even bigger retcons. Not only had the Doctor previously hidden on Earth and used a Chameleon Arch before the events of “Human Nature,” but also, this version of the Doctor represented an entire cycle of numerous lifetimes previously hidden from the Doctor and the audience.
Solidified in “The Timeless Children,” the Doctor’s past was not what we thought it was, and the history of Time Lord tech — specifically regeneration — was actually stolen from another, as yet fully revealed alien race.
Going into the new, impending era of Doctor Who in 2023 and 2024, the full history of the Doctor’s hidden lives remains one of the show’s biggest mysteries. But, none of it would have been possible had “Human Nature” not happened first. Once Who canon created the ability for the Doctor to have hidden in plain sight, and passed for one of us, without actual knowledge of who they were, several dominos fell. The name of the show has often been considered a long-running joke since we don’t actually know the Doctor’s name. But after “Human Nature,” we could have all started calling the show, Doctor Anybody, and we wouldn’t have been wrong.
