Two Time Travel Tricks

I have been reading thrillers in which fugitives manage to stay out of sight, confounding the police or anyone else who might be looking for them. But imagine how a time traveller would be able to stay out of sight. You don't want anyone to find you or know where you are for a whole year? Then just travel forward in time for a year.

Imagine this scenario. Everard travels from June 1984 to a single day in June !987, then returns to June 1984. On that day in June 1987, Shalten briefs Everard about the Bactrian letter, which was discovered in 1985. Some time between June 1984 and the relevant day in 1985, Shalten deletes the discovery of the Bactrian letter. Thus, he deletes his briefing of Everard about that letter. But that does not prevent Everard from arriving back in June 1984 knowing about that letter and able to act on the knowledge.

(I am trying to retrieve some sense from Shalten's confused account here.)

1902 AD

The Shield Of Time, 1902 A.D.

Shalten debriefs Everard back in 1902 because:

"'In your position among us, you need to know the whole truth. For you to learn it later in this century could pose a hazard. Causational loops can be very subtle. Your experiences and accomplishments in Bactria must continue to have happened. Therefore you must be informed well pastward of our preparations for them. I thought you would enjoy a visit to my Belle Epoque.'" (p. 122) 

Everard's activities in Bactria cannot cease to have happened because of any temporal changes that are made in the twentieth century. Nevertheless, Shalten has made some complicated changes. By deleting 1985 A. D., pp. 11-16, when Garshin was given the Bactrian letter, he has also deleted 1987 A. D., pp. 66-76, when he himself informed Everard of the Bactrian letter. Everard remembers experiences that did not occur in the current timeline. Shalten has to delete events that he wants to delete while preserving events that he wants to preserve. No doubt Unattached agents know how to do this.

Meanwhile, at least, Poul Anderson presents a vivid description of the Boulevard St. Germain in Paris in 1902, a world that, as Everard reflects, will crash to ruin in a dozen years. See 1902 AD.

Dealing With What Is Not

Even if a Time Patrolman maintains that the timeline that he is currently experiencing is the only timeline that has ever existed in any sense whatsoever, he must nevertheless refer to other, presumably completely non-existent, timelines that he "remembers" or has been told about. Manse Everard "remembers" timelines in which:

the Scipios died at Ticinus, Hannibal sacked Rome and the Carthaginians won the Second Punic War;

the Popes won the medieval church-state conflict;

the Emperors won it;

Keith Denison played the role of Cyrus the Great;

a knight and a friar disappeared from within a treasure house in South America;

there was a sensation about a Bactrian letter.

Wanda Tamberly is shown records of time gone awry. Guion informs Everard of anomalous variations in reality and reminds him that the question of how many temporal catastrophes there have been is inherently unanswerable. Everard wonders whether they in the far future are (will be) making whatever desperate provision they can for a chaos that they cannot chart and therefore cannot turn aside.

On the other hand, if the currently experienced timeline really were the only existent timeline, then there would be no need to prevent its deletion. Certainly the fact remains that, since we are experiencing this timeline now, it follows that we are indeed experiencing it now. (If p, then p.)

1985 A.D. x 2

Poul Anderson, The Shield Of Time (New York, 1991).

In 1985 A.D., pp. 11-16, Russian Army Private Garshin wanders alone in Afghanistan after an ambush until a captain appears like "...an angel from his grandmother's heaven..." (p. 11) and gives him a box - which contains the Bactrian letter - with instructions about how to return to his base and to get the box conveyed to the appropriate authorities whereas, in 1985 A.D., p. 123, Garshin wanders alone.

The Time Patrol has planted false evidence, then removed it from the timeline. How did they do it? Maybe:

the Patrol agent who plays the role of the captain is from the far future;
first, he travels from the far future to the far past;
his instructions are - travel forward to 1985 to give the box to Garshin, then return home unless, just before setting off to 1985, you receive a countermanding order to skip past 1985 and proceed straight home;
when Shalten is informed that Everard has killed or captured the remaining Exaltationists, he transmits that countermanding order.

See also:

1985 AD;
The Fall And The Time-Stream.

Trapping The Last Exaltationists

The siege of Bactra (see here) was not a world-changing event but Shalten fakes evidence that it could have been and ensures that this evidence is publicized during a year when there is reason to believe that some Exaltationists may have been lurking. If the Exaltationists heed Shalten's spurious evidence and try to change the course of history from 209 B.C., then Patrolmen will be waiting for them.

When the last Exaltationists have been apprehended, Shalten has the spurious evidence deleted from the timeline. This strikes to me as both unnecessary and dangerous. What other events, necessary to the Patrol's plan, might unintentionally be deleted in the process?

Shalten's and Everard's 1987 conversation about the Bactrian letter "now" never occurred. Nevertheless, Everard of course remembers it and it is unnecessary for Shalten to discuss the letter again with Everard in 1902 in order to ensure that he retains the memory. That part of the dialogue definitely makes no sense.

Patrol agents like Shalten have some nuanced way to manipulate events in order to ensure exactly the right combination of the preservation of the preferred timeline with deletion of potentially harmful happenings but we are told very little of how they do it.

Starvation

I prefer to post while rereading. Otherwise, many details would be missed unless extensive notes were taken, which would be too much like hard work. Blogging remains a leisure activity although, with this subject matter, it could become a research project.

To post while reading or rereading is to engage in a dialogue. The text replies to earlier remarks. I realized that the Exaltationists could not after all have changed history in Bactria because their intelligence source, the Bactrian letter, was a fake.

I have argued that the Tulat would starve while paying tribute to the Cloud People - and Aryuk's family nearly does. They fail to deliver their last tribute for the season. Aryuk explains to Wanda:

"'This has been a hard summer. Fish, shellfish, small game, everything was scant. We went hungry because we must spend time getting things and traveling for the Mammoth Slayers...We must make ready for winter. If we worked any more for the Mammoth Slayers, we would starve.'" (The Shield Of Time, p. 206)

I still think that they would have starved by now anyway but my present point is that the text goes a lot further towards recognizing this issue than I was giving it credit for.

Tinkering With Reality

In Poul Anderson's The Shield Of Time (New York, 1991), chapters are unnumbered. Each is headed by a year date, sometimes by the same year date. Thus, we must distinguish between 1985 A.D. pp. 11-16 and 1985 A.D., p. 123. These opening and concluding chapters of Part Two are set in the same year but in different timelines. On pp. 11-16, a mysterious Russian captain gives Private Garshin the casket containing the Bactrian letter whereas p. 123 informs us that the Patrol has cancelled that event so that Garshin does not meet the captain.

(This explains something else. The letter saying that Euthydemus had sallied out of the city was a fake. Thus, the Exaltationists did not have any opportunity to help Antiochus to kill Euthydemus on a battlefield after all.)

If the events of pp. 11-16 have been annulled, then so have the events of 1987 A.D., pp. 66-76, when Shalten informed Everard of the Bactrian letter. However, Everard traveled to 209 A.D., pp. 17-25, 34-41, 47-65, 77-94, 102-118, with memories of the Bactrian letter and therefore returned to the twentieth century with those memories. It is therefore redundant for Shalten afterwards to meet Everard in 1902 A.D., pp. 119-122, and say:

"In your position among us, you need to know the whole truth. For you to learn it later in this century could pose a hazard. Causational loops can be very subtle. Your experiences and accomplishments in Bactria must continue to have happened. Therefore you must be informed well pastward of our preparations for them.'" (p. 122)

Shalten is getting all mixed up. No annulment of events in 1985 can affect what Everard did two millennia earlier. And, as already argued, since Everard took his memories of the Bactrian letter to 209 BC, those memories returned with him even though the event in which he was informed of the Bactrian letter has been cancelled.