I don't think that Sci-fi has inherent philosophical value at all.
Personally I don't much care about this genre and it's not the reason why I love 2001: A Space Odyssey.
When I see this movie I don't feel like I'm watching sci-fi at all.
Man I managed to download Stalker and Solaris rips since days ago, but haven't got the time to see them yet, I'm major curious.
Solaris is maybe one of the slower movies to watch. I found though that the slow transitional pace helps make something extraordinary seem real. It's really long. But fantastic!