Monday, 28 July 2014
"'An incipient causal loop is always dangerous...It can set up a resonance, and the changes of history that that produces can multiply catastrophically. The single way to make it safe is to close it. When the Worm Ouroboros is biting his own tail, he can't devour anything else.'"
-Poul Anderson, Time Patrol (New York, 2006), p. 449.
"An incipient causal loop..." must mean a potential causal circle that needs action by the Time Patrol to complete it but what is a resonance? Carl Farness visiting the fourth century Goths has been mistaken by them for Odin. Their literature relates that Odin appeared in a battle and betrayed his followers. In the twentieth century, Everard tells Carl that he must travel back once more to enact that betrayal.
If Carl refuses, then history cannot and will not retroactively change because of his refusal. He and Everard are conversing in a timeline where the betrayal did happen and was recorded in literature. However, the first consequence of his refusal would be that the Carl who did perform the betrayal will return to the twentieth century. To prevent that duplication of himself, the Carl who is talking to Everard must travel back to the fourth century in order to be the Carl who appeared and betrayed his followers.
The second consequence might be that anyone returning from a period earlier than the fourth century could arrive in an altered timeline where the betrayal had not happened. Is this potential double consequence what is meant by "a resonance"?