Nonsense? Well...yes and no. The fact that when you visit people in Mode 2 OOBEs and appear to see what was on their minds at the time, appear at times to speak to something
which, my best guess is that it is a representation of their unconscious selves pretty much tells me that not everything in Inception
is fiction. Shared dreaming would also back this up and the Tenoi tribe of Malasia have a lot of experience with this as it is part of their culture to talk about dreams at breakfast...it's another life.
The lucid dreaming element is obvious. You can do this. Anyone can. Reality checks can be effective. The "architect" concept in the film is nonsense. You don't need architects. You can also visit someone regardless of whether they are asleep or awake. The "inception" concept (planting an idea in someone's mind) is another matter, I don't know whether this is possible or not but it doesn't seem feasible. Even in hypnosis, you cannot make someone do something that goes against their morals...even in a highly suggestive state. Even if you could do an "inception" on someone, there would be no way to tell whether it really worked or not. How would you know for sure that the idea the individual had, after your dream visit
, was a result of this and not a manifestation of his/her mind which happened to coincide with your dream?
There is such a thing as 'dream incubation' but it is more evident on a personal level. You can certainly appear to obtain information from those you visit in OOBEs and lucid dreams, either 'mind stuff', the gist of what they are doing in the physical (as in slightly inaccurate replicas of waking reality in Mode 2 OOBEs) and seemingly accurate info (Mode 1 OOBEs) but as for influencing or controlling someone's mind like in Inception...well, that's the science-fictiony part in my opinion. But who knows...what is science-fiction today may become a different story tomorrow. Hollywood tends to spice things up anyway. It's all about the spice for sales...