1 January 1956 was my seventh birthday. In that year, Poul Anderson's first Nicholas van Rijn story, "Margin of Profit," was published. In September of that year, I started to attend a boarding school in Scotland. (I have already referred to a spatial location, somewhere in Scotland, and to a
time - but this is the time of our experience, not of physicists or science fiction writers.)
As yet unaware of adult prose sf, I read comic strips either featuring "spacemen" (men in spacesuits) or set, as I put it at the time, "before spaceships were invented." Little did I know that Nicholas van Rijn existed and was a "spaceman" not only because he traveled through space but also because, specifically in "Margin of Profit," he dons a spacesuit and goes EVA.
I also read the Classics Illustrated adaptation of
The Time Machine and, later, a short story in which a time traveler changed the course of past events. Later again, I reasoned that changing the past was impossible until Poul Anderson's
Guardians Of Time persuaded me otherwise in the early 1960s, by which time I was at a boarding school in the Republic of Ireland. Now, of course, I realize that mutable and immutable pasts are equally valid time travel premises and that Anderson wrote definitively about both.
Thus, I knew of alternative histories generated by time travelers but did not yet suspect that such histories might coexist with ours in parallel timelines not generated by any extra-temporal interventions. In one sense, alternative history fiction, also written by Anderson, accurately reflects our experience. We are continually choosing between alternatives and reconsidering or regretting past choices. Scientists no longer favor causal determinism. However, even if it were the case that, when I choose between options A and B, I am causally determined to choose A, not B, it would also still be the case that I would need to make the choice in order to learn the choice. I might have inhabited a universe where I had been causally determined to choose B, not A.
Even if alternative histories do not physically exist in parallel timelines, we are conceptually surrounded by them in every decision-making process. If I had died in a car accident in 1967 before starting University, then:
decades of my life and experience would not have occurred;
my daughter and granddaughter would not exist;
Sheila would have married someone else and had other children and would now be living somewhere else;
our son in law would have moved to the Lancaster district but would not have met our daughter;
other people would have done all the jobs that I have worked in;
this blog would not exist;
someone else would now be living at 44, Blades St, Lancaster.
These are, or at least were, real possibilities. And some people in those other possible worlds would speculate about alternative histories. We recognize SM Stirling's Eric von Shrakenberg as a man who would willingly serve a better cause if he had been born in a different timeline.
