In "On Imaginary Science, " Poul Anderson explained how a careful rereading of Olaf Stapledon's future history and cosmic history helped him to handle the temporal transitions in Tau Zero but he also explained something else, also connected to time.
I read Anderson's Guardians Of Time when it was first published in hardback in Britain (1960?). I had thought that "changing the past was impossible" but a Time Patrol trainer convinced me that it was possible. Later, of course, I realized that these are alternative fictional premises but that the latter is much harder to do right.
I never understood this - at the Time Patrol Academy:
"There were a couple of romances. No Portrait of Jennie stuff..."
-Poul Anderson, Time Patrol (New York, 2006), p. 14.
A decade and a half later, married and living in Lancaster, I watched a feature film on TV. I think that I had missed the beginning of the film and do not remember inquiring as to its title. The film can be described as "haunting" and as "not quite time travel." A man keeps meeting a girl who is impossibly older each time they meet. She says something like, "I am growing up for you." I have always remembered that at one point he says something like "Wind blows, sea flows, God knows," to which she replies, "I'm sure He does." I thought that "Grass grows" could have been included in the rhyme. The film ended with some sort of climax at sea. I do not remember the details. I thought that an older woman character was suddenly going to manifest as an older version of the girl but she didn't although something was realized in a scene involving her.
In the1990's, when I read that Richard Matheson's Bid Time Return had been filmed as Somewhere In Time, I thought that maybe this was the film but I read the book and it was an entirely different story - although Matheson's novel is an excellent romantic time travel story like Audrey Niffenegger's The Time Traveler's Wife.
Anderson, listing a few of what he calls routine fictional uses of time travel, writes:
"Perhaps the most famous, because beautiful and haunting, is Robert Nathan's Portrait of Jennie which brings in time travel by sheer fiat."
-Poul Anderson, "On Imaginary Science" IN Anderson, The Collected Short Works Of Poul Anderson, Volume 2: The Queen Of Air And Darkness (Framingham, MA, 2009), pp. 105-113 AT pp. 107-108.
(But is it quite time travel?)
This evening, I read "On Imaginary Science," googled "Robert Nathan Portrait of Jennie" and found that this was the film whose title I had never known.
