Doctor Who: 7 Key Themes That Defined The Matt Smith Era

3. Predestination and the Destiny Trap

While "Doctor Who" has always abounded with ontological paradoxes and time-bending shenanigans, Smith's run has been filled to the brim with temporal trickery and head-scratching chicken-or-the-egg moments. Many story arcs are built around the idea of an immovable future catastrophe that the Doctor must - against all laws of time - strive to prevent, but in doing so must contend with changing a fixed point in time, which are the immovable, unalterable points in the fabric of history that cannot be tampered with, lest the whole tapestry of reality come crashing down. Basically, any attempt to change history ultimately accomplishes nothing more than the fulfillment of the destiny trap, which is the idea that attempting to meddle with a previously established timeline will only result in yourself becoming a part of it: imagine if you went back in time and tried to shoot Hitler, only for the bullet to lodge in his brain and fill him with a hatred of all things Kosher. Over and over again the writers present us with the idea that Disaster X is irrevocable, unshakeable, and forever a-fixed in the fabric of history. And every time, the conclusion is that no, it totally wasn't. We're constantly told that you can't change the future any more than you can your own past. And over the course of three series, the Doctor does both. Even Eleven's last stand on the clock-tower of Trenzalore (we refuse to mention the name of the actual town in this article) is one that ends and ultimately revels in a good kick in the groin to the Stupid Grown-Ups with Their Stupid Grown Up Rules. In the end, it's Amy Pond who sums it up most succinctly: "Changing the future. It's called marriage." It doesn't mean that tying the knot will give you destiny-defying abilities or even that your father-in-law is obligated to give a time-travelling DeLorean as a wedding present. It hearkens back to Doctor's own humanist leanings and implies that human beings have agency through choice rather than imprisonment through fate. The future is always in flux.