The Peter Capaldi Theory That Would Change Everything In Doctor Who

"Doctor Who" debuted in 1963, and though it had a failed revival when the movie came out in 1986, it returned in 2005 with an all-new cast and crew. Since Christopher Eccleston took on the mantle of the Ninth Doctor, "Doctor Who" has continued uninterrupted, bringing a new generation of fans. The revival now has 13 seasons, introducing five new Doctors, all of whom have adopted unique personalities while maintaining the knowledge of their previous incarnations. The show also features a handful of travel companions, and of course, countless dangerous aliens and thrilling adventures. 

For as long as "Doctor Who" has been on the air, it comes as no surprise that viewers have come up with their own theories. From speculation about the Doctor's name being "42" to the First Doctor actually not being the first one — this actually has been confirmed in "The Timeless Child" — there are many thoughts about the titular character. One such theory is specifically about the Eleventh Doctor's (Matt Smith) regeneration into the Twelfth Doctor, and what it means for the character and his history. 

Peter Capaldi's casting was a little bit of a shock, especially because he is so much older than David Tennant and Matt Smith, who played the 10th and 11th Doctors, respectively. Some believed he might have been too old to take on the part after Smith, who was the youngest person to play the Time Lord (via Daily Mail). However, it is possible that the stark contrast implies he has forgiven himself for the Time War. 

This theory was first posed after the 50th-anniversary special, "The Day of the Doctor." Fan Alexbfree8 brought the theory to Reddit, mentioning that the much-older War Doctor (John Hurt) asks his future selves, "Do you have to talk like children? What is it that makes you so ashamed of being a grown-up?" Alexbfree8 explained that the Doctor has taken on younger bodies following this incident because he is ashamed, as the War Doctor says. He feels so much remorse over the Time War, so as a result, he becomes "a very different person than the War Doctor" in order to "distance himself from that person." 

By the end of his life, the Eleventh Doctor starts to realize that the "guilt he first felt at Nine won't leave him alone," and he needs to stop being someone he's not. The decision to finally grow up and take responsibility for his actions manifests itself in his regeneration into an older form; he is "older, wiser, more-self assured, less guilt-ridden, and more confident" now that he allows himself to move forward.