Soft vs hard is based on how closely the world tracks with modern physics/science. As such even just FTL is soft, let alone everything else that doesn’t fit.
> Soft vs hard is based on how closely the world tracks with modern physics/science
Maybe it's not productive to quibble about definitions like this, but FWIW I don't agree with this criteria. I would argue Greg Egan's work, for example, is just about the "hardest" sci-fi there is, and yet much of that work takes place in universes that are entirely unlike our own.
Personally, I think what makes for "hard" sci-fi is that the rules of the universe are well-laid-out and consistent, and that the story springs (at least in some significant part) out of the consequences of those rules. That may mean a story set in the "future", where we have new technology or discover new physics, or "alternate universe" sci-fi like Egan's.
> Soft vs hard is based on how closely the world tracks with modern physics/science
Maybe it's not productive to quibble about definitions like this, but FWIW I don't agree with this criteria. I would argue Greg Egan's work, for example, is just about the "hardest" sci-fi there is, and yet much of that work takes place in universes that are entirely unlike our own.
Personally, I think what makes for "hard" sci-fi is that the rules of the universe are well-laid-out and consistent, and that the story springs (at least in some significant part) out of the consequences of those rules. That may mean a story set in the "future", where we have new technology or discover new physics, or "alternate universe" sci-fi like Egan's.