Bootstrap paradox

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Bootstrap paradox
The Twelfth Doctor reflects on the question of music and the bootstrap paradox (TV: Before the Flood [+]Loading...["Before the Flood (TV story)"])

A bootstrap paradox was a sequence of events in which an event was among the causes of another event, which in turn is among the causes of the first-mentioned event. A hypothetical example was a time traveller who was a fan of Beethoven went into the past to meet his hero. However, he discovers that Beethoven doesn’t exist. The traveller decides to publish all the works of Beethoven himself, thus becoming Beethoven. The confusing question is, who composed Beethoven’s Fifth? (TV: Before the Flood [+]Loading...["Before the Flood (TV story)"])

The name could also be rendered as "Bootstrap Paradox" (GAME: Worlds Apart [+]Loading...["Worlds Apart (video game)"]) and such constructs were also known as causal loops. (AUDIO: The Two Rivers [+]Loading...["The Two Rivers (audio story)"])


The Twelfth Doctor influenced Davros as a child when he inadvertently arrived on Skaro during the Thousand Year War. When the young Davros recognised that the stranger was stunned when he gave his name to him, this inspired Davros to reach for greatness and become "a brilliant scientist". Being responsible for the creation of the Daleks, Davros had many confrontations with earlier incarnations of the Doctor before catching up with the Twelfth Doctor in the Hybrid Incident. (TV: The Magician's Apprentice [+]Loading...["The Magician's Apprentice (TV story)"], PROSE: Davros, Dark Lord of Skaro)

Manning a Cyber-Scout craft, a Mondasian Cyber-Scout was sent on a mission to travel through a cosmic cloud that appeared the same time an ape-servant had arrived, to find the ape's home planet and convert their species. The Cyberman came through the cloud and was fired at by missiles by the Lizard Kings of Mondas, in an era before Mondas broke away from Earth. The missiles missed the Cyber-Scout craft, but the recoil injured it and damaged its voicebox. Noticing the Cyberman's technology was not unlike their own, the Lizard Kings decided to study the Cyber-Scout through vivisection and sent an ape-servant into the cloud to its world. The ape-servant inside the craft was the same ape that inspired the Cybermen to send the Cyber-Scout through the cosmic cloud in Mondas' future. (COMIC: The Prodigal Returns)

The Bad Wolf meme was a Bootstrap Paradox. (GAME: Worlds Apart [+]Loading...["Worlds Apart (video game)"])

The Bad Wolf entity's existence was the result of such a causal arrangement. Rose Tyler only looked into the heart of the TARDIS, creating the Bad Wolf, after she was motivated by seeing Bad Wolf graffiti, which she created after becoming the Bad Wolf herself, (TV: Rose [+]Loading...["Rose (TV story)"], Aliens of London [+]Loading...["Aliens of London (TV story)"], The Parting of the Ways [+]Loading...["The Parting of the Ways (TV story)"]) making the entire affair a Bootstrap Paradox. (GAME: Worlds Apart [+]Loading...["Worlds Apart (video game)"])

The Doctor's TARDIS created a bootstrap paradox when it sensed Jenny's existence. However, by instinctively transporting the Tenth Doctor to her, it arrived too soon and, conseqeuntly, meant the Tenth Doctor created her using the Progenation machine. Therefore, as the Doctor said, Jenny's birth was "a paradox, an endless paradox." (TV: The Doctor's Daughter [+]Loading...["The Doctor's Daughter (TV story)"])

Donna Noble created a bootstrap paradox by giving the idea of Miss Marple to Agatha Christie. Agatha got the idea of Miss Marple from Donna's knowledge of the future works by her. Although Agatha's memories of that night were wiped by her link with the Vespiform, the Tenth Doctor explains to Donna that some of the information may have "kept bleeding through... like Miss Marple". (TV: The Unicorn and the Wasp [+]Loading...["The Unicorn and the Wasp (TV story)"])

Joel Finch inadvertently inspired the pose of God in Michelangelo's Creation of Adam for the Sistine Chapel, after having been sent back to 1511 by a Weeping Angel. Joel studied the works of Michelangelo in the 21st century, and suggested this new pose based on his own recollections of the painting. Joel may have also invented the sandwich. (AUDIO: Fallen Angels)

It was the ArcHivist Hegelia's theory that the Isomorph Cybermen, the last remnant of the Neomorph Cyber-subspecies of 26th century Telos who were stranded in the 1980s after failing to change history by preventing the destruction of Mondas, made contact with the early CyberFaction on the dark side of the Moon. With the support and influence of the Isomorphs' cyber-technology, the CyberFaction would leave the Moon, splitting into separate subspecies that would ultimately come together and create the first of the Neomorph Cybermen on Telos. (AUDIO: The Ultimate Cybermen)

A bootstrap paradox was created while the Twelfth Doctor and Clara Oswald were at the Drum: the Doctor gained the idea of using a hologram of a ghost version of himself, through Clara who had seen the ghost Doctor and told the Doctor about it. (TV: Before the Flood [+]Loading...["Before the Flood (TV story)"])

For that matter, the circumstances that brought the Eleventh Doctor and Clara Oswald together came about largely because of a bootstrap paradox. The Doctor sought Clara out after having met two of her "splinters", at the Dalek Asylum, (TV: Asylum of the Daleks [+]Loading...["Asylum of the Daleks (TV story)"]) and in Victorian London. (TV: The Snowmen) The Doctor eventually found the original Clara and took her on as a companion in the hopes of solving the mystery of how she seemed to have lived and died in different times and places. Their travels together would ultimately lead to the event that saw the creation of Clara's "splinters", including those that the Doctor previously met, thus setting him on course to find the original Clara to begin with. (TV: The Name of the Doctor [+]Loading...["The Name of the Doctor (TV story)"])

According to one account, the Fifth Doctor's recognition of the phrase wibbly wobbly, timey wimey, (TV: Time Crash [+]Loading...["Time Crash (TV story)"]) seemingly coined by his tenth incarnation, (TV: Blink [+]Loading...["Blink (TV story)"]) was as a result of hearing River Song say it during an adventure she had with that incarnation. (AUDIO: A Requiem for the Doctor) River herself learned the phrase from the Eleventh Doctor, (TV: The Wedding of River Song [+]Loading...["The Wedding of River Song (TV story)"], The Angels Take Manhattan [+]Loading...["The Angels Take Manhattan (TV story)"]) and assured the Fifth Doctor that it would grow on him in time. (AUDIO: A Requiem for the Doctor)

Amy Pond named her daughter, Melody Pond, after her childhood friend Mels, unaware that Mels was her daughter, making Melody her own namesake. Additionally, Melody started going by the name River Song after learning of her future identity from the Eleventh Doctor and her parents. (TV: Let's Kill Hitler [+]Loading...["Let's Kill Hitler (TV story)"])

Iris Wildthyme and Panda created a bootstrap paradox in order to divert a potentially dangerous future involving malevolent aliens from the future. (PROSE: Iris Wildthyme and the Unholy Ghost)

The involvement of the Dalek Restoration Empire in the Kotturuh crisis owed itself to a bootstrap paradox. (PROSE: The Last Message) After the Doctor had defeated the Dalek Time Squad, (PROSE: All Flesh is Grass, AUDIO: Mutually Assured Destruction) a surviving Dalek drone transmitted a message warning others about the Doctor's actions and the temporal fluctuations. Hearing this message, the Emperor of the Restoration decided to investigate, making sure to place the drone's past self on the Time Squad when he formed it. (PROSE: The Last Message) Whilst the Tenth Doctor was surprised to discover the Restoration Empire, who had no recollection of fighting the Time War, (COMIC: Defender of the Daleks) the Kotturuh crisis had helped to ensure that it would occur as the Dalek Prime Strategist and, by his reckoning, the Emperor, would plan for war with the Time Lords. (PROSE: Exit Strategy)

When the Spy Master left Team TARDIS on a falling plane, the Thirteenth Doctor recorded a video to inform them how to survive, doing so because she had been informed by Ryan Sinclair that he had already done so. (TV: Spyfall [+]Loading...["Spyfall (TV story)"])

When the Tenth Doctor found himself on Mira, he questioned who had deposited him on such a remote world, (AUDIO: Buying Time) later learning that he was the culprit, using a time tunnel to abduct his past self so he would be set on the path to stop the time tunnels. Privy to the Doctor thinking aloud, the Nun noted that she hated bootstrap paradoxes, a sentiment that the Doctor agreed with. (AUDIO: The Wrong Woman) When this adventure led to the Doctor being embroiled in the Dalek-Movellan War in the Pre-Time War universe, he wondered if him ensuring his own past was a bootstrap paradox. (AUDIO: The Triumph of Davros)

The creation of the Doctor Ogron was a bootstrap paradox. Upon first meeting his counterpart and being informed that the Ogron had arrived on Gallifrey in a future version of his own TARDIS, the Eighth Doctor agreed to travel to the Planet. While there, the Doctor's genetic material was used by the Overseer was used to create the Doctor Ogron. Understanding the paradox, the Doctor sent the Doctor Ogron to Gallifrey in his TARDIS to complete the loop. (AUDIO: Planet of the Ogrons)

Later in the Last Great Time War, the Eighth Doctor and Bliss travelled to parallel universe where they befriended an an alternate Davros. When the alternate Davros attempted to aid them in stopping the Dalek Strategist, he encountered a future version of himself, one corrupted by the Daleks, who manipulated his past self into ensuring he would come to be, one who knew what to say because he remembered being told by his future self. (AUDIO: Palindrome)

When the Tenth Doctor and Martha Jones found themselves stranded in 1969, the Doctor used a transcript that he'd been given by Sally Sparrow in the 2000s[nb 1] to communicate with herself a year in Sally's past. The conversation that Sally had with the Doctor led to the completion of Larry Nightingale's transcript allowing Sally to gift it to a version of the Tenth Doctor who had yet to encounter her so he could use it in 1969. (TV: Blink [+]Loading...["Blink (TV story)"])

When trapped on Sto, the Twelfth Doctor used the influence he eventually gained to fashion the Titanic after its Terran counterpart, so his younger self could encounter the ship. (COMIC: A Confusion of Angels)

After their first adventures together, the Eighth Doctor understood that his friendship with Josie Day was a bootstrap paradox, one that the Twelfth Doctor had arranged because he remembered going on those adventures. (COMIC: A Matter of Life and Death)

By one account of the Genesis Incident, the Fourth Doctor's actions were ultimately part of a bootstrap paradox, ensuring that Dalek history would play out as he had already experienced it. (PROSE: The Dalek Problem) Another account of the creation of the Daleks credited the Fourteenth Doctor with coining the name "Dalek" from his memory, leading the Kaled Castavillian to apply it to Davros's creation. This same account also saw the Doctor destroy the proposed multi-dextrous claw and replace it with a plunger, to Davros's approval. (TV: Destination: Skaro [+]Loading...["Destination: Skaro (TV story)"])

In an aborted timeline where the Doctor's TARDIS crashed on the Tick-Tock World, the First Doctor and his companions saw an echo of Ian Chesterton's future self who warned them that they would die on this planet. A few days later, Ian delivered the warning to their past selves, repeating what he remembered hearing. (AUDIO: Tick-Tock World)

After witnessing River Song's death in the Library, the Tenth Doctor asked himself why his future incarnation had given her a sonic screwdriver given he had years to devise a way to save her life since he had met her chronologically out of order. On inspection, he discovered the sonic screwdriver contained a neural relay with River Song's data ghost, giving the Doctor just enough time to upload River's Data ghost into the Library's computer core and giving her another chance at life inside the Library's computer. (TV: Forest of the Dead [+]Loading...["Forest of the Dead (TV story)"]) Following this event, the Doctor would remember River's death through his eleventh incarnation and eventually marry her. (TV: The Wedding of River Song [+]Loading...["The Wedding of River Song (TV story)"]) By their final meeting in his twelfth incarnation on Darillium, the Doctor gifted River the sonic screwdriver after scanning her with it, implanting her data ghost into the neural relay, ready for his tenth incarnation to save her with it. Therefore, since the idea to use the screwdriver came from his tenth incarnation discovering the twelfth incarnation used it, the incident created a Bootstrap paradox. (TV: The Husbands of River Song [+]Loading...["The Husbands of River Song (TV story)"])

Two incarnations of the Master, the Saxon Master and Missy created a Bootstrap paradox. When searching for the Saxon Master's TARDIS, he reveals to his future incarnation that he had broken his dematerialisation circuit, causing Missy to shove the Master against a wall and give him a spare one she had on her person, telling him to always keep a spare one on hand. Missy remarked she recalled a woman had done this to her when she was the Saxon Master, making her realise the woman who she remembered was Missy herself. Later on, Missy decided to ally with the Twelfth Doctor, stabbing the Saxon Master, who then fatally wounded her in retaliation. Consequently, Missy had created her own existence in triggering her predecessor's regeneration. (TV: The Doctor Falls [+]Loading...["The Doctor Falls (TV story)"])

The First Doctor's first regeneration was the result of a Bootstrap paradox, as he initially refused to regenerate. However, after encountering the Twelfth Doctor who was also refusing to regenerate, and seeing the kind of person he would become in the future, the First Doctor changed his mind and decided to regenerate. However, the Second Doctor did not remember the event as their timelines were not synchronised. (TV: Twice Upon a Time [+]Loading...["Twice Upon a Time (TV story)"])

Emerging from their bi-generation with an improved emotional, mental and optimistic mindset from that of his predecessor, the Fifteenth Doctor would convince the Fourteenth Doctor to take a brief retirement on Earth, as a form of rehab in order for him to recover from the emotional and mental trauma he had been going through for years now. As the older of the two incarnations, the Fifteenth Doctor had already benefited from the rest and rehab on Earth. Seeing how well adjusted and happy his successor was convinced the Fourteenth Doctor to go into his retirement, allowing the Fifteenth Doctor to emerge from the Fourteenth Doctor's bi-generation with the personality that he had. Having done their rehab "out of order", the Doctors had created a bootstrap paradox. (TV: The Giggle [+]Loading...["The Giggle (TV story)"])


  1. While Blink [+]Loading...["Blink (TV story)"] itself uncontroversially sets its main setting in 2007 and "twenty minutes to Red Hatching" a year later in 2008—as Kathy Nightingale's letter describes taking "one breath in 2007 and the next in 1920", and the Tenth Doctor's side of his conversation with Sally Sparrow in 1969 happens 38 years before Sally says hers—these are contradicted by heavily conflicting dates in the Redacted audio series later on regarding both Kathy's disappearance and the Red Hatching. In Angels, Abby McPhail identifies 2008 as the year of Kathy's disappearance, which suggests 2009 as the year of the Red Hatching. In Salvation, the Thirteenth Doctor recognises the Red Hatching as the cause of death of Andy Proctor, who was last seen by his daughter Cleo "nearly 20 years" before 2022 according to Recruits.