Time set by "Human beings" is stupid: they can't tell, 'cos don't know, when it began/begin but they believe it goes just straight/forward even unknowing where'e the end of it: linear, monotonous, simple... stupid.
I've seen both, Soderbergh and Tarkovskij versions; I'd choose the first one, if I must do it. In Soderbergh movie there's, paradoxically, THE "idea": a man, a woman, a dream; two living beings and "me" who thinks watching them.
I read Lem's book not entirely; I didn't feel the "necessity" to read on and I didn't want to make any comparison between the images seen "through" the movies and the word/images of Lem's mind.
Julian Barbour has the best description of the illusion of time in western literature in The End of Time. But we already knew that all along.... Time is so relative the American symbol for it is old "Father Time" who gets replaced by an infant each New Year.
When I first saw Soderberth's Solaris I was disappointed because it didn't live up to my memory of Tarkovsky's -- then when I watched Tarkovsky's again, I was disappointed because it didn't live up to being better than Soderbergh's!