Bootstrap paradox

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 common example was an individual who grew with a piece of music, then traveled back in time and introduced the song into the past, with the resultant question being: Who composed the song? (AUDIO: The Shadow Play, TV: Before the Flood)

Godfather Morlock explained the "bog-standard time paradox" to Faction Paradox initiates including Cousin Eliza. He would expand on the paradox by explaining that every atom affects every other atom in the universe by a great "ripple effect" expanding through time, so going back in time and taking only a single breath of air will remake the present. (AUDIO: The Shadow Play)

The Twelfth Doctor once explained the paradox (TV: Before the Flood) to Clara in a mental TARDIS console room. (TV: Heaven Sent) A bootstrap paradox was created while the Doctor and Clara 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)

The Bad Wolf entity's existence was the result of a bootstrap paradox. 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, Aliens of London, The Parting of the Ways)