Scifi is fiction about where science might take us, how modern tech might impact society. It is foreshadowing a potential future. So stuff set in the past, generally, isnt considered scifi unless it somehow describes a potential future. This separates scifi from technothrillers (tom clancy et al) that are tech-heavy but set today rather than in the future.
> So stuff set in the past, generally, isnt considered scifi unless it somehow describes a potential future.
This makes literally no sense to me. Any definition of the future that doesn't include the past is just fiction, and consequently, any past is a potential future.
What you're saying sounds more like "If it doesn't have greater than present levels of 'technology', then it's not science fiction."
Which seems incredibly limiting and ignoring of the central genesis of the genre, as you've pointed out -- science.
Science is a verb, not a noun.
The idea of pointing at something in a book and saying "That's science" (and correspondingly, pointing at something in other fiction and saying "That's not science") is odd.
Where do Mary Shelley, Jules Verne, or H.G. Wells fit in your definition?
Scifi is fiction about where science might take us, how modern tech might impact society. It is foreshadowing a potential future. So stuff set in the past, generally, isnt considered scifi unless it somehow describes a potential future. This separates scifi from technothrillers (tom clancy et al) that are tech-heavy but set today rather than in the future.