I’ve not read the Heinlein one, but I think Gerrold’s book spends too much time on the character’s narcissistic self-obsession. The bit where he kills Jesus of Nazareth was kind of interesting, but very short. Having decided that changing history would be boring for the history changer, Gerrold spent most of the book on a sad narcissist’s pathological self-regard.
If we’re doing recommendations, you might like [del]IDW’s[/del] Colinet & Charretier’s The Infinite Loop. I thought it was a bit wacky, but it does play with the idea of time-agent ethics in its own way.
Yeah, isn’t it a book about the character’s narcissistic self-obsession?
There is this episode of South Park, in which they attempt to change the future because they’re sick of all the time-travelling illegals taking their jobs.
And I want to know more about this “Hisler” person. Apparently he’s already been wiped from history!
There are multiple timelines at play. At least Starlog had a bunch of article about “the other Marty McFly” decades ago. That Marty left from lone pines mall, not twin pines mall like the one we follow, but we know he exists, because our marty sees him leave while trying to save the doc.
Then they proceed to constantly change history in each and every episode. Guess who killed Lincoln? Booth? No, it was our main bad guy!
In all fairness, Lincoln had it coming.
OK, so I read Palimpsest at that link. That was impressive.
Interesting that by the end, it becomes a conflict over what future history is supposed to be, between conservative and progressive philosophies, with time travel a means more than just an end. Well done.
In Callahan’s Lady, by Spider Robinson, a character deduces a time traveler’s mission thusly: They are both a time traveler and ethical, therefore their only possible mission is to save the world.
I should ignore the BttF hijack, since these posts don’t have anything to do with ethical elements, but…
I have gone into this repeatedly on the boards over the years and have a list of rules that cover pretty much everything about BttF time travel. Summary: novel changes to the timeline propagate slowly, reversions propagate quickly, and time travelers are insulated from changewaves while actually being displaced. (There’s more to it, but those cover the quoted issues well enough.)
Hm. I don’t think I’ve ever addressed this specific point, mostly because I’ve never seen it raised, even in threads specifically alleging plot holes in BttF. I don’t see a problem with it. Marty-Prime in 1985-2 (the version in which his family was happy and successful) told Doc that he was planning to take Jennifer for a ride in the new truck before Doc persuaded him to go to 2015. The version of 2015 they traveled to was the one established before Doc’s intervention, so it was downstream of Marty and Jennifer taking that ride and getting in a wreck. When Marty finally returned to 1985-1 at the end of BttF III, he followed through on his stated plan for the day, so he and Jennifer ended up at the same place–but his new perspective changed the outcome.
Stephen King’s 11/22/1963 covers all these bases. And it’s a book everybody should read.
Yes, destroying the universe is a bit of an ethical problem.
I’m a bit of a nerd, I can’t help myself sometimes.
That’s exactly where I picked it up from. 
One big ethical problem with time travel is that (assuming you can change the past) any change you make will have both negative and positive consequences. You might kill Hisler (or his alternative universe counterpart Hitler), and create a new timeline with untold benefits for the vast majority of humankind; but there will also be some unintended consequences. People will suffer who did not suffer before; people will die who did not die before - some or many individuals will never even be born.
By changing history, you are directly responsible for all that new suffering or non-existence - perhaps it would be possible to use a utilitarian assessment on the state of the universe, to see if the ratio of unhappiness versus happiness was smaller or greater. But that isn’t much consolation for the people who are actually suffering, or those who do not exist in the new timeline (not that they have much capacity to care one way or the other).
Yes, as in all consequentialist analysis. You act like we don’t do this in non-time-travel contexts.
The difference in a time travel context is that you can compare the effects of action a/and action b/, and evaluate the positive and negative consequences. If you had unlimited access to time travel, you could do this for any action, and come to realise that any decision you make has negative as well as positive aspects. This could easily result in terminal indecision - an unwillingness to act in any circumstance.
Like doing the nasty in the past-y?
Kind of. The First Fifteen Lives of Harry August by Clare Norton deals with a particular flavor of time travel, that of the “looped life” - not like in The Man Who Folded Himself mentioned by a few people, more like what happens in Replay by Ken Grimwood. I heartily recommend both books, BTW, on top of the several recommendations for TMWFH.
In these books, some people “die” only to continue consciousness from a previous point in their own life, but with all the memories of what happened, and what they learned, in past iterations. So you can now make different choices, including leveraging knowledge of the future, such as picking stocks, betting on sports events, and so on (until such time as your twiddling alters events). But when you die and get “reset”, you have to start over again. Also, in both books, for plot reasons more than “how does that work exactly” reasons, “loopers” are basically in cohorts: two who live in the same era will remember each others’ actions in prior iterations as well as their own.
It’s a philosophical question, only tangentially raised in the books as it’s not the focus of either story, as to what happens to those “altered timelines” from the POV of the looper. Do they continue forward? Does the looper have an ethical responsibility to the people whose lives they manipulated with foreknowledge, after the point of their death? There is also a discussion between two of them on the ethics of holding a grudge against a “linear” person across iterations for something they’ve seen him do repeatedly in the “future”.
Interestingly, a major ethical reason cited against “making big waves” in the Harry August novel is that in changing the future, they would disrupt and possibly eliminate future birth events of others of their kind, as it has been seen that loopers whose births were avoided in one iteration are not reborn in the next (not as loopers, anyway) - they’re “killed”. So just as a looper born in the 20th Century wouldn’t appreciate being twiddled out of (repeated) existence by some schmuck trying to kill or help out Napoleon, he owes the same courtesy to loopers of the 21st Century not to go and try to kill Hitler.
Then there is the “12 Monkeys” theory of time travel that the past is immutable. Nothing the time traveler can do will change the future because it has already happened. If you go back in time to kill Hitler, for example, you will fail. How do we know? Because Hitler did in fact grow into adulthood.
Or more perversely, the time traveler actually causes the action he tries to prevent. For example, go back to 1865 and attempt to convince John Wilkes Booth not to assassinate Lincoln. The time traveler finds out that Booth didn’t originally have such an intention, but the time traveler plants the idea in his head.
Since time travel is fiction, it is a fun debate to have, but no firm answers.