Poul Anderson's Legacies

Time Travel
Can anyone top the Time Patrol? Audrey Niffenegger's The Time Traveler's Wife is at least an excellent circular causality novel.

Cosmic SF
I know that there is much post-Anderson cosmic sf, e.g., by Gregory Benford, but have not really kept up with it.

Alternative Histories
We have seen that SM Stirling has developed this sub-genre further than Anderson.

Future Histories...
...in which extrasolar colonies are isolated for centuries, then reincorporated into an interstellar civilization. We are currently finding that Jerry Pournelle's CoDominium future history fits well into this sub-sub-genre.

Hard Fantasy?

Time Travel Fiction

Most new time travel fiction is at worst incoherent or at best unoriginal.

Incoherence
I have discussed illogicalities in time travel fiction here, here and here. It is pointless to readdress such issues at length every time they recur. The Mammoth Book Of Time Travel SF contains a four page story which I read to the end only because of its brevity. The surprise ending was that the story described an impossible time travel scenario only because its narrator was insane! Thus, this story is not sf. (But how many of its readers thought that it was making sense?)

If a time traveler departs now to change an event in my past and succeeds, then he generates a divergent timeline in which that event happened differently and in which I now remember it differently but I do not, in the original timeline, continue to remember the first version of the event only to discover that the event has "now" been changed so that it did not occur as I remember it!

Unoriginality
It is insufficient merely to (re)state the circular causality paradox although The Time Traveler's Wife demonstrates that it remains possible to present new and surprising implications of that paradox, as Poul Anderson had done in his three independent time travel novels.

It is necessary to spell out, preferably briefly, precisely which version of a divergent or multiple timelines scenario an author is using but not, of course, to present the mere idea as if it were a novelty. Anderson's Time Patrol series presents an extremely subtle mutable timeline theory which, I think, contains incoherencies as stated by the characters but which nevertheless warrants careful study and also makes for intriguing and haunting stories.

Wells, Anderson And Niffeneger

Poul Anderson's Time Patrolmen are like HG Wells' Time Traveler in that they sit on their time machines. Audrey Niffeneger's Henry DeTamble is like Anderson's Jack Havig in that he time travels without a time machine. However, Detamble travels involuntarily to psychologically significant times and places - thus, the novel is neither historical nor futuristic but contemporary - and, logically, does not take his clothes with him. Arriving naked at unexpected destinations is a whole new problem for a time traveler.

DeTamble, like the Time Patrollers, space-time jumps instantaneously (from his own perspective) whereas Havig, like the Time Traveler, sees his environment fast forward or rewind. Niffeneger presents an intricate circular causality romantic novel. Thus, like several other writers, she develops one aspect of time travel where Anderson develops every aspect and can be compared favorably to authors as diverse as Wells, Asimov and Niffeneger.

Three Culminations

I thought that Jack Finney's two Time novels and Poul Anderson's two-volume Time Patrol series were the two culminations of time travel fiction but Audrey Niffeneger's The Time Traveler's Wife (the one of these works that also happens to have been filmed) joined the list as soon as I had read it and I hope that there will be a sequel, The Time Traveler's Daughter.

Finney: nostalgic time travel to earlier decades in the United States;
Niffeneger: a contemporary novel of relationships involving time travel;
Anderson: historical periods and processes and futuristic speculations.

Niffeneger perfects the circular causality paradox. Thus, her novel needs to be compared with Anderson's three non-series time travel novels rather than with his Time Patrol series. Unlike the three by Anderson, Niffeneger's novel is a longer work, is neither historical nor futuristic but entirely contemporary and deals with personal relationships, not with any wider issues.

Henry tells Claire not to sign a drawing because he has seen it unsigned in the future but she signs it... But events remain consistent despite this. (She was right to trim off the signature because they want their known future to be their experienced future. A time traveler who sets out to change events might succeed in which case they will be in a different timeline, which is not what they want.) See here.

What I am saying here is that I recommend not only Poul Anderson's time travel works but also certain others for comparison and that these others definitely include The Time Traveler's Wife.

Knowing The Past

I recommend Audrey Niffenegger's The Time Traveler's Wife as a novel that ingeniously addresses the same kind of time travel paradoxes as Poul Anderson's There Will Be Time (New York, 1973).

In Anderson's novel, if a time traveler tries to change a known event, then something happens to prevent the attempted change so that the time traveler soon learns to stop trying. If he persists, then he might be stopped by a fatal accident. Thus, often, when an events occurs that a time traveler does not like, the only reason why he does not change it is because he does not try to change it. In these cases, there need not be any preventing event waiting in the wings to occur if necessary.

In the time travel fight described a few posts ago, if Havig had seen himself kill Mendoza, then he would have killed Mendoza but, because he does not see himself do this, he does not do it.

This does strain credulity and plausibility. Havig's group could conduct some controlled experiments in attempted causality violation, e.g., a time traveler tries to appear at a time and place at which it is known that he did not appear in order to find out what, if anything, will prevent him. If nothing prevents him, then they are instantly in a different scenario, more like that of the Time Patrol. They can never be completely sure that this will not occur.

If a lot of time travelers try to change a lot of known events, then the laws of probability will have to change to prevent them. For example, will a hundred time travelers each suffer a fatal heart attack just before setting off on a mission to change the past?