wilting - Without meaning to go into another long-winded discussion about sci-fi... 
"Of course it is (implausible)! You don't believe that anyone is going to start chanting incantations at you anytime soon and send you into incoherent vaguely religious breakdown now do you? Or that static on a screen will do similar? Or in reincarnation? Or in vampires?"
By definition, sci-fi as a genre deals with situations that are not around us, in the world we live in, here and now. So no, I don't believe anyone will be hacking my brain with a few words etc. But a book can talk about this stuff and still be plausible - i.e. If ancient words that allow others to take control of your brain are found tomorrow, or if a viral military project went out of control and superhuman 'people' were unleashed on the world, or if a clearly artificial but 100,000-year-old perfect rectangular stone was found buried on the moon... What would happen? How would people react? How would their dynamics change? What would be the conflicts that arise. Those need to be plausible for good sci-fi.
"science fiction book, I'm afraid it remains implausible/incredible/extremely unlikely... thought provoking possibly, plausible, no."
Improbable (= unlikely) is not the same thing as implausible (= hard to believe). The starting point of a book can be improbable, but what makes a good book is whether what follows is plausible. That is, whether or not the author has thought it all through and created an internally consistent universe where dynamics change in believable ways.
That is where Iain Banks' books fail imho. It's all wishy washy, stuff happening in idealistic ways that would never happen, no real reason why they should happen, and no explanation of why they've happened. Like robots walking around people, living like people, sitting down playing chess with people, relaxing on the couch and having conversations with people. Why on earth would they do that?
Re Sparrow - "it's not very "techy", it is primarily a human drama of exploration, arrogance and tragedy on the premise of first contact with an alien planet."
I'm all for 1st contact stories but... a Jesuit priest dealing with an alien civilisation
doesn't sound like my cup of tea. And it's written by a woman so I can imagine that it's a human drama, tragedy, blah blah so again probably not for me. Thanks for trying, though 