Time Travel And Survival

If you have time travel and your future is about to become uninhabitable, then you can survive by traveling far enough into the past, as in Poul Anderson's "Wildcat" and also in a Star Trek episode, whereas, if there is time travel in a mutable timeline, then maybe you need a temporal police force, as in Anderson's Time Patrol series: two examples of time travel as a means to survival, the first covered by Anderson in a single short story, the second in a long series of stories and novels, and, since this a late night post, we will leave it there till the morning when I expect to finish rereading and posting about "Wildcat" - tempus fugit.

Guardians Of Time?

We cannot change the past. I can regret past actions and resolve to act differently from now on but cannot change how I did act.

The past is partly known and completely immutable. Our understanding of World War II can change but not the fact that there was a World War II with certain dates, certain major events and turning points and many details, known or unknown. It is conceivable that someone might seem to himself to have been transported from 2020 to 1940, thus to be living among the events of World War II. However, if he makes the events of 1940-1945 different from the way that he remembers they were recorded, then, wherever or whenever he is, he is not in the World War II that is part of our known history. There must be some other explanation of his experiences.

All this has been discussed before, of course, but maybe we can clarify a principle? The proposition that the past cannot be changed applies not only to our familiar experience of time but also to any time travel scenario. Travel through time would involve travel to the past and the past cannot be changed. Anyone who, e.g., assassinates Hitler in 1940 is not in our past, therefore has not time traveled.

The Time Patrol And The Temporal Bureau II

The Temporal Bureau exists so that Robert Heinlein can tell a single circular causality short story whereas the Time Patrol exists so that Poul Anderson can present a series of stories of different lengths and even novels about interventions in historical periods. Thus, "'- All You Zombies -'" cannot have a sequel whereas the Time Patrol was eventually expanded to a considerably greater length than its original four stories.

Both organizations close causal circles although the Patrol sometimes does this in order to prevent causality violations which are impossible in the Temporal Bureau timeline.

The Patrol operates from prehuman geological epochs at least until the time of its post-human founders a million years hence. We know that at least one Bureau operative has been in pre-Christian Crete but the organization's headquarters seem to be under the Rockies in 1992. There is no indication that the Bureau operates any later than the twentieth century.

One of the Bureau's "By-laws of Time" is: "Ancestors Are Just People," which is relevant to the Patrol agent, Carl Farness.

The Time Patrol And The Temporal Bureau

"An Unattached agent of the Time Patrol drew on unlimited funds."
-Poul Anderson, The Shield Of Time (New York, 1991), PART ONE, 1987 A. D., p. 4.

"The Temporal Bureau doesn't care how much you spend (it costs nothing)..."
-Robert Heinlein, "'- All You Zombies -'" IN Heinlein, The Unpleasant Profession Of Jonathan Hoag (London, 1980), pp. 126-137 AT p.134.

The Patrol sends time criminals to an exile planet whereas the Bureau can exile its own court-martialed members to a year in, e.g., 1974 when there is strict rationing and forced labor. In Poul Anderson's "My Object All Sublime," (see here) a future civilization exiles criminal to unpleasant past periods.

The Temporal Bureau is named once in a single short story whereas the Time Patrol fills two long volumes.

Knowledge Of The Future And The Past

HG Wells' Time Traveler knows the general course of the future because he has traveled through it and returned to his present.

In James Blish's The Quincunx Of Time,  Service agents know of the future because they receive messages from future periods, then ensure that the events described in those messages occur.

Poul Anderson's Time Patrol agents observe unrecorded past events in order to know the course of the history that they must protect from extratemporal interference.

Anderson's contending Wardens and Rangers, living in our future, try to influence their future by controlling unrecorded details of past history.

In Anderson's There Will Be Time, two groups of mutant time travelers contend. One group changes the significance of known events.

The temporal agents in Robert Heinlein's "'- All You Zombies -'" cannot prevent events but sometimes cause them.

Heinlein's Lazarus Long visits the period of his childhood but to no good purpose.

Isaac Asimov's time traveling "Eternals" change events to maximize human happiness until they themselves are prevented from existing but I argue that Asimov's narrative is incoherent. See The Logic of Time Travel: Part II, here.

There is time travel between two periods of Brian Aldiss' future history, Galaxies Like Grains Of Sand.

Closing Down On John C. Wright's Time Travel Article

For a time travel problem on Comics Appreciation, see here.

It has been great but we are nearly finished.

Wright quotes, apparently uncritically, the absurd idea in a Back To The Future film that a man whose birth has been prevented would fade out of existence but he does go on to say that this is absurd. If your birth is prevented, then you do not exist and fade out. You do not exist. I have yet to arrive home and find a teenage girl who fades out of existence, saying: "I am the daughter that you would have had if you had not successfully practiced contraception sixteen years ago." Exactly the same logic - consistency between propositions - applies to time travel scenarios as to non-time-travel scenarios.

I have been told that Dinosaur Beach by Keith Laumer is a good time travel novel but have not read it so I looked forward to reading Wright's plot summary. However, having read that summary, I now think that the novel sounds far too complicated and potentially contradictory to be interesting to read. I can be persuaded otherwise, of course, but, for the time being, Dinosaur Beach is not on my reading list.

Time Travel Is Sometimes Very Annoying... IV

See the previous post here.

In the Fritz Leiber story, if the man trying to prevent his own future murder keeps revisiting the events immediately preceding the murder, then surely he will run into and interfere with his younger and older selves?

Wright recommends David Gerrold's The Man Who Folded Himself. I do not:

The Man Who Folded Himself by David Gerrold expounds a successive timelines scenario but immediately contradicts it in practice. Gerrold’s scenario: Moving either backwards or forwards in time takes a time traveler into a second timeline identical with the first except for any changes made by the time traveler, the first such change being his arrival. He leaves timeline 1 forever. If he continues to travel, then timeline 3 incorporates his arrival from timeline 2 and duplicates his arrival in timeline 2 unless this duplication is prevented by the time traveler after arriving in timeline 3, e.g., if he had arrived in timeline 2 during World War II but, then, in timeline 3, prevented World War II, then this would also prevent his arrival in the 1939-1945 period in timeline 3.

After expounding this scenario, Gerrold then describes the following transaction: the time traveler travels a short distance into the future, confers with his future self, then returns to the present to make use of his knowledge from the future. This could happen in a single timeline but, in Gerrold’s scenario, the transaction should be as follows:

the time traveller disappears forever from timeline 1;
no future self greets him in timeline 2;
he returns to the present in timeline 3;
later in timeline 3, he greets that timeline’s duplicate of his past self who had originally arrived in timeline 2;
that duplicate returns to the present in timeline 4 and there meets the duplicate of the self who had returned to the present in timeline 3.

Thus, by pulling this stunt, the time traveler should have unintentionally duplicated himself, although Gerrold does not realize this.
-copied from here.