Today, whenever sci-fi fans are talking enthusiastically about time paradoxes in time-travel storylines, it's tempting to evoke the immortal words of the 10th Doctor (David Tennant) and say: “Wibbly Wobbly Timey Wimey.” This phrase comes from the famous episode “Blink,” in which predestination paradoxes save the day. But, arguably, the better, and more mind-blowing Doctor Who paradox happened in 2015 with the two-part story “Under the Lake” and “Before the Flood.” Eight years ago, on October 10, 2015, Doctor Who threw down with one of the best bootstraps paradoxes of all time, giving other sci-fi franchises — like Loki Season 2 — a near-perfect model of how to make sense of the infinite loop of the bootstrap paradox. Spoilers ahead.
