So he bet on Juliana escaping her way out of a trunk with three armed resistance members set to kill her. That she would find her way to her mothers house and randomly see a picture of the guy that she was thinking of and ask her mom about it to reveal his true identity. He bet on her defecting to the Nazi's (just in the nick of time i might add) and John Smith would personally vouch for her as he desperately needed info on the high castle man. He then bet that Juliana would AGAIN escape being murdered by two more resistance members only to shoot the man in the back to prevent nuclear war.
He just saw her at key points. He knows that she gets to those points, not always knowing exactly how she gets there. He also explains that not everyone does (he sees people's future in the reels of film that never ends up happening), but that she's an exception to that rule--she always makes it to those points.
Also, you're not being asked to accept these things as resembling anything like reality. This is a television show and given that it is in the science-fiction genre, they get quite a bit of canvas to paint on.
But maybe this isn't for you. We can supply you with a whole lot of sci-fi films involving alternate realities / timelines that you should perhaps steer clear of.
Not true at all... alternate realities are a staple of science fiction... real sci-fi, not that crap that calls itself sci-fi but is really space opera at best.
The various films are coming from a variety of parallel Earths - they made that part quite clear.
For something to be considered Science Fiction, there has to be some element of science advancing the story, either physical or chemistry-based. The story may also center around technology (Hard Science Fiction- Aasimov, Heinlein, Clark), or have a future setting (science fiction's roots are based in speculative fiction, after all).
The Man in the High Castle, on the other hand, has none of this. It is the very definition of Alternate History fiction: a genre of fiction in which the author speculates on how the course of history might have been altered if a particular historical event had had a different outcome.
Keep telling yourself that - it won't change the fact at all.
Ursula LeGuin is considered science fiction and science is in the far background of her stories.
Indeed, science fiction is not a very good name for the genre, but the classics of the genre have always been more about exploring the human condition, understanding changes in culture over time - the fact is, laser blaster space opera IS NOT automatically science fiction, and indeed the crap that "SyFy" puts out demonstrates that ad infinitim. Stories that explore these scenarios yet don't have ANY "gadget" are considered more science fiction than space opera is.
"Alternative history" stories generally are just considered general fiction or in a subgenre of historical fiction - but MitHC is about the multiverse around us - about how actions taken in one reality could affect others in "nearby" realities. It's not just two alternate timelines we're talking about here - but a multitude.
Really... this is as much within the realm of sci-fi as anything Asimov ever wrote about (and I should know, I've read most of it), despite your incorrect assumptions/assertions about the genre.
Please just read some Phillip K. Dick (and stop pretending you know what you're saying).
Furthermore, the parallel realities in The Man in the High Castle is, as I mentioned above, not a science-based element in the story. So far, there has been no use of science or technology to explain why these parallel realities exist, or how some people are able to travel from one to the other. In fact, it's a mystical element that serves as the plot device that (sort of) explains this- the I Ching!
Quantum Leap is a good example of a show that uses technology/science to explain how the main character is able to jump through time and into parallel realities, which certainly makes it Science Fiction. This is in stark contrast to The Man in the High Castle's metaphysical/fantasy-based plot devices.
The Man in the High Castle is not Science Fiction.
Well, the Hugo awards are very prestigious in the world of Science Fiction Literature, and the Hugo in 1963 for best science fiction novel was given to Philip K. Dick's book upon which this TV show is based.
The people who run the Hugo awards would most likely strongly disagree with you that the book "The Man in the High Castle", which included the same idea of a person being able to experience an alternate reality/parallel universe other than his own, was NOT science fiction.
Granted, the book and the TV show differ in that in the book Abendsen is the one who can experience the other reality/parallel universe, while in the TV version it is Tagomi who can travel to the other reality.
And I'd say traveling from one reality to an alternate reality (traveling between parallel universes) is quite the 'science-fictiony' thing.