BUT, I have to say, after watching the movie, Brian's interpretation of the film as something of a parody of his life, though objectively wrong, was not completely unreasonable. There are a heck of a lot similarities and coincidences to see if you're looking for them.
Right. But there really is no way to
objectively evaluate whether or not Brian's interpretation of what was on the screen was valid or not. So, as you've done, you look at it subjectively - from Brian's p.o.v. at the time, and then you see that, like you said, it's "not completely unreasonaable." I would use stronger language that that - it's actually "very reasonable," for Brian to be spooked; his response was valid, given the way his life had been going up to that point. What Brian was wrong about was the idea that the film was
intentionally financed and made with the specific purpose of spooking Brian Wilson, individually. That was basically paranoia, which is generally thought of as a kind of psychological defense mechanism to guard against, and/or rationalize emotions and feelings (such as, in Brian's case, tremendous anxiety and fear) whose true cause remains hidden or denied. Remember, Brian was already hearing voices by this point, which it's fair to assume was a secret that he wasn't telling anyone. (that is, I've never read any comment from anyone who knew Brian in the 1960s saying, "yeah, Brian was telling me that he was hearing voices." All they saw was that this guy was "weird" or "paranoid" or whatever)
Seconds, in the end, is a mind-gangster film (like
Manchurian Candidate). Mind control. Of course, what happens to Rock Hudson in the movie represents what would happen to Brian in real life during the 1980s, and in many ways what had been occurring in his life under the Hawthorne-based abuse and mind-gangsterism of [fill-in-the-blank] In
Seconds, the mind gangsters are doctors, technicians, businessmen (if I remember correctly). In
Manchurian Candidate the mind-gangsters are communists, and with the preeminent mind-gangster being the mother of the main character, which means that the guy is basically screwed.
Apprently, while filming
Seconds, Rock Hudson (who it can be said, was in some ways leading a publlicly false life - living a lie) had some sort of an emotional breakdown. Another anecdote: The screenwriter of
Seconds took a friend of his to a screening of the film when it came out. In the middle of the movie, the friend gets up and walks out of the theater. The writer follows him and asks, what's wrong, dont you like the movie? The friend tells him, something like, "I can't watch this movie. This is my life up there on screen, I can't take it." (source for this is a book on Rock Hudson called "Idol") So there's that; Brian wasn't alone. And in fact the movie did poorly at the box office probably because people stayed away once word got out.