About Time Travel

This blog has been used less because most of my blogging about time travel has been about works by Poul Anderson and therefore has been on the Poul Anderson Appreciation blog. For example, the previous post on this blog:

Time Travel And Survival

- was copied from Poul Anderson Appreciation. It ended by saying that there would be further posts about Anderson's short story, "Wildcat." Posts about that story can be found here.

More recent posts on time travel have been:

Responses To Time Travel

What We Experience And How We Talk About It

What We Experience..., Continued

Three Dimensions Of Space And Two Of Time

Time Travel Illogicalities

Time Travel Illogicalities II

Time And Consciousness

Anderson's major works on time travel are:

The Time Patrol series

The Corridors Of Time

There Will Be Time

The Dancer From Atlantis

"Flight to Forever"

We have also discussed relevant works by other authors, e.g.:

The Time Machine

The Time Traveller's Wife

The Anubis Gates

Bring The Jubilee

The Door Into Summer

The Technicolor Time Machine

Time And Again by Jack Finney

Lest Darkness Fall

Bid Time Return

My major analyses of time travel are:

The Logic of Time Travel: Part I

The Logic of Time Travel: Part II

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 is 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.

Time Travel Is Sometimes Very Annoying... III

See John C. Wright's article, here.

In "Try to Change the Past" by Fritz Leiber, a man prevents his future self from being shot in the forehead only to see that future self killed by a micrometeorite puncturing his forehead exactly when the bullet would have. Poul Anderson presents this idea of inertia of events in "Time Patrol" but not on that unlikely a basis. In the Time Patrol universe, that man would have saved his future self. I have read little of Leiber's Time War series and have not liked the little that I have read. Too many ideas unrelated to time travel, and also insufficiently explained, are introduced. The time travel happens almost off-stage and the causality violations are not described coherently. I think that the narrator suddenly has a scar that she didn't have before (or something like that) but I am not about to try to dig out The Big Time to check the text.

Another Ad For Another Blog

Copied from Poul Anderson Appreciation:

I am continuing to read and discuss John C. Wright's article on time travel. See here. My second post on this topic refers to Alfred Bester, Charles Dickens and Superman but not to Poul Anderson so that post will remain on the Logic of Time Travel blog whereas its predecessor will probably be copied here since the page view count continues to indicate that more people read this blog than that one. I value discussions of time, logic, free will, Heinlein's "By His Bootstraps" and Anderson's There Will Be Time and want to share them as widely as possible.

In Audrey Niffenegger's The Time Traveler's Wife, Henry sees his future wife draw a picture and tells her not to sign it because he has seen it unsigned in the future. See signs it. When he returns to the future, he looks for the picture on the wall and it is not there. It has fallen behind the fridge. When he retrieves it, it is unsigned. She had trimmed the signature off because she did not want to risk Henry returning to a future other than the one he remembered. In this novel, there seems to be only a single consistent timeline but the characters want to make sure of that.

My comment would be: in a single consistent timeline, logic dictates that, if the artist were the sort of person who would not have trimmed off the signature, then Henry would have seen her draw the picture and would not have told her not to sign it because he would remember having seen it signed in the future. This has taken us away from Poul Anderson but it remains relevant to the kind of time travel in his There Will Be Time.

Time Travel Is Sometimes Very Annoying But Not Always II

I am continuing to read John C. Wright's article on time travel. See here.

Wright refers to "The Men Who Murdered Mohammed" by Alfred Bester, which I have not read. If you change the past, then you become insubstantial and unable to change anything. Why?

Wright writes:

"...you can change the past, but if you do, the only thing you can do is eliminate yourself."

I find this contradictory. If you can change the past, then you do more that eliminate yourself. Also, to become insubstantial is not to be eliminated.

There was an idea that, from the moment of arriving in the past, you would be an insubstantial observer as in Charles Dickens' A Christmas Carol or in Superman's first Kryptonite story - although not in subsequent Superman stories. However, insubstantial viewing of the past is not time travel.

Time Travel Is Sometimes Very Annoying But Not Always

See "Time Travel is Always Annoying" by John C. Wright, here.

I will try to summarize:

how can time travel coexist with the appearances both of free will and of cause and effect?;

in Robert Heinlein's "By His Bootstraps," free will is an illusion;

free will seems to exist when you are acting but is seen not to exist when a later you travels to the time of your action;

when you try to change an earlier event, you will find that you have a good reason not to;

this is unsatisfactory because the story stars a robot programmed to think that he has free will although he does not;

each scene makes sense but the whole picture does not;

the character has to be drunk, forgetful, mistaken, ignorant of crucial facts or provided with an artificial reason why he does not want to change the past;

Wilson does not notice that the other guys whom he meets have the same face;

in any such story, the main character makes no decisions and is a passive observer.

I disagree. By "free will," I understand only absence of constraint. "Free will" in this sense is compatible with causal determination of all our decisions and thus of our subsequent actions. Indeed, how else can decisions and actions be explained? Maybe by an uncaused random neuronic interaction, like a cerebral quantum fluctuation? OK. But we do not choose to have one interaction/fluctuation rather than another occur inside our brains. We have no more control over this than we do of any of the external and internal causes that affect our mental processes. So we are "free" only to the extent that we are not constrained. When we make moral or legal judgments about past actions, our own or others', we think of ourselves as agents who could have acted otherwise for a practical reason: we want to influence future actions. On a past occasion, I was tempted, so I "sinned"/offended. On a future occasion, I will again be tempted but this time I will also fear punishment/disapproval so I will be less likely to offend.

A time traveler is just as free or unfree as anyone else. He cannot prevent from occurring an event that does in fact occur but nor can anyone else. Wilson decides to change the course of a remembered conversation by reciting a nursery rhyme but cannot, in the stress of the moment, remember a single nursery rhyme so he instead says something that is appropriate at that stage of the conversation and we can confirm by turning back a few pages that that is precisely what was said at that stage of the conversation.

Wilson I is tired and drunk and thinks that he recognizes Wilson II but cannot place him. Wilson II recognizes Wilsons I and III. None of them recognizes Wilson IV because he is older and bearded  with an air of authority. When he finds that he has good reason not to change past events, then Wilson freely chooses not to change past events.

In Poul Anderson's There Will Be Time, Jack Havig changes not known events but their significance. Thus, the Eyrie recruits Havig and Boris in Jerusalem. When Havig breaks from the Eyrie and organizes against it, he sends Boris to Jerusalem to infiltrate the Eyrie. Havig and his colleagues use their time travel to facilitate the beginnings of a dynamic civilization and to kick-start interstellar travel, not just to manipulate a static society on Earth. Their story moves outward, not just round in its groove.

John C. Wright On Time Travel

http://www.scifiwright.com/2019/05/time-travel-is-always-annoying/#more-23360, here.

Book Review: There Will Be Time

See "Science Fiction and Other Suspect Ruminations," here.

Link To Golden Apples Of The West

Golden Apples Of The West: Bring The Jubilee

Time Travel And Two Future Histories

An early birthday present is The Sky-Blue Wolves by S.M. Stirling, published 2018. I commend the title.

Whereas Julian May wrote a time travel tetralogy and a future history both set in a single timeline, Stirling wrote a time travel trilogy set in a timeline divergent from that of his Change/Emberverse future history. The Pliocene Exile influences the Intervention whereas the temporally displaced Nantucket cannot influence the Emberverse.

We have come a long way from Volume I of the Nantucket Trilogy to Volume XIV (?) of the Emberverse, Stirling's longest series. We have already been told that the current Black Chamber alternative history is a trilogy.

We look forward to further volumes and series in 2019 and the years ahead when the Earth of our timeline will definitely go through some changes. 

Time Travel In Future Histories

(i) I do not accept Time Enough For Love as an addition to Heinlein's Future History.

(ii) Olaf Stapledon's Last Men time travel mentally and one narrates the history.

(iii) In Poul Anderson's There Will Be Time, time travelers visit the period of the Maurai History.

(iv) In Larry Niven's Known Space future history:

"'...that funny religion on Altair One. They thought they could travel in time.'
"Yes sir. When we landed the infantry they were all gone.'
"'They must have all committed suicide with disintegrators.'"
-Larry Niven, "The Warriors" IN Niven, Tales Of Known Space (New York, 1975), pp. 135-151 AT p. 145.

2025

It was 2025 and the current international crisis was approaching its crescendo. Everyone was glued to the TV above the bar:

"This country stands ready to defend its rights..."

Not everyone. One guy sat further back, grinning, apparently amused by our excitement. Puzzled by his response, and because there was nowhere to sit at the bar, I moved back to near where he was sitting.

"It won't happen," he confidently informed me. I waited for him to enlighten me. At last, he vouchsafed:

"This crisis will not escalate all the way for another twenty years."

"How do you know?"

"I've been there."

That was all. He had been where? He had lived through such protracted conflicts before? All of us had done that. Then:

"I must make a call."

He stood up and walked toward the phone booth at the back of the room. There was a burst of excitement from the bar. I glanced that way, then looked down at the table where I noticed that the mysterious stranger had left a coin. It was dated 2026. I looked quickly at the phone booth. It was empty.

Twenty years.

Mask

My phone buzzed. "M will see you now."

Ascending to the eighth floor of SIS HQ, I walked down the long corridor between the muted hum of Communications and the distant burr of the Armory. (Most of the Armory is in the basement but some new weapons are tested up here, where few enter.)

Because the red light was on above the door marked "Time Travel Section: Director," I walked in and sat facing M who was as usual seated behind a transparent bullet-proof screen and was masked. I had never seen his face. I also suspected that I was the only current agent of the Section although I might have glimpsed one or two from the future - who could have included myself, of course.

Looking up from his computer screen and addressing me by my Section number, he said, "T.T.1, your first three missions have been experimental but successful..."

In each case, I had traveled only a few months into the past. Careful neither to be recognized nor to affect what happened, I had discovered the explanations of some mysterious events. For example, we now knew who had burgled a house in Knightsbridge. In future, we would be able either to take action against that individual or to feed him disinformation. But I knew that the Section was intended for something greater than these minor investigations.

M continued, "Your next mission will be harder but is guaranteed to succeed. You will travel back thirty years and will engage in actions that will affect the course of events..."

I interrupted, "Thirty years ago, there was no Time Travel Section..."

On my previous missions, I had had the option, if I encountered difficulties in the past, of ringing an emergency number at the Section. I had not been told in advance whether I had needed to do this and in fact I had not needed to. Nevertheless, Section members had known from the outset that they might have to help agents from the future and procedures were in place, starting with the unique password that I would use, with the letter "f" among its digits.

"You will have to operate without backup - unless someone from further ahead helps you..."

He paused to consider this possibility. Then:

"There was no Section then. Your mission will be to found it. You'll need this."

Taking off his mask, he passed it under his bullet-proof screen.

Communicating Through Time

HG Wells' Time Traveler sends the small model Time Machine into either the past or the future. He does not know which. There is no way for it to stop or return. Poul Anderson's Time Patrolmen communicate between years by tiny robot shuttles with automatic shunts to prevent them from arriving together.

Manse Everard sends a shuttle from his New York apartment in 1954 to the London office, June 25, 1894, and, a few minutes later, receives a typed note from J. Mainwethering, inviting him to attend with a qualified British agent at 12:00 midnight on June 26, 1894. Getting an ok (by phone?) from his immediate superior, Everard sends a note to Whitcomb in 1947 and Whitcomb agrees.

Going to the Patrol warehouse, Everard gets a timecycle, like a motorcycle without wheels or kickstand but with two saddles and an antigravity propulsion unit. He departs to a warehouse in London, 1947, when he is joined by Whitcomb, and they depart for Mainwethering's gas-lit office in 1894.

Like Wells updated.