Collider argues that the defining line in Doctor Who is the Fourth Doctor’s question, “Do I have the right?”, from the 1975 serial “Genesis of the Daleks”. Faced with the chance to destroy the Daleks before they become a galactic threat, the Doctor’s hesitation establishes the character’s moral opposition to killing, even when doing so might avert future atrocities.

The story sends the Doctor, played by Tom Baker, to Skaro on the Time Lords’ orders to prevent the Daleks’ creation. After wiring their incubation room with explosives, he tells Sarah Jane Smith that destroying them could make him no better than the evil they will embody; the blast is ultimately triggered accidentally by a Dalek. The article also highlights the serial’s portrayal of Davros, the war-ravaged planet Skaro, and the contrast between the Doctor’s pacifism and the Time Lords’ willingness to use extreme measures.