Science Fiction, Swords And The Supernatural

Science fiction is an extremely broad category. I have just read the concluding section of Prince Of Outcasts by SM Stirling. Soldiers fight with swords and the supernatural is manifested so is this sf? Yes. The story is set in the future. The premise of the series is that advanced technology has stopped working, therefore warfare has returned to swords. The supernatural is a transcosmic consciousness that had emerged from a previous cosmos and has caused the Change. Thus, every feature of the plot is scientifically rationalized although several volumes read like fantasy. The companion series, about the temporally displaced Nantucket, is time travel sf without any supernatural manifestations beyond the as yet unexplained Change/Event. The premise of divergent timelines allows for any number of coexisting scenarios as demonstrated in other novels and series by Stirling. Sf as a literary ghetto developed various stereotypes and cliches but is always able to transcend them.

A-Mortality

According to Yuval Noah Harari, Sapiens: A Brief History of Humankind (London, 2014), human agelessness and post-organic intelligences may be imminent.

In Poul Anderson's sf:

aging is ended in World Without Stars and in The Boat Of A Million Years;

post-organic intelligences coexist with human beings in the Harvest of Stars Tetralogy and supersede humanity in Genesis.

I have referred to Anderson's ageless characters, Hugh Valland and Hanno, as "immortal" although they are not immune to either accident or violence. See Two Unaging Men. Harari contributes appropriate terminology:

"A few serious scholars suggest that by 2050, some humans will become a-mortal (not immortal, because they could still die of some accident, but a-mortal, meaning that in the absence of fatal trauma their lives could be extended indefinitely.)" (p. 301)

I think that John W. Campbell said, "The first immortal man has already been born." By googling, I found similar claims. See here.

See also Hanno, Lazarus Long And John Carter.