What the auteur theory came out of was the sense that film was a processed,
impersonal medium with a contrived, stagey air of unreality about it.
Imagine the studio system as a conveyor belt, each movie emerging with
'product' stamped on it. What it had in glamour and accessibility and
shorthand realism, it lacked in psychological purity. So, they sniffed out
what struck them as psychologically pure and canonized it.

The dream of Truffaut especially was to create a cinema as intensely
personal, as pure, as the novel. As a form, at its best, the novel gives you
a sense of the internal life of the writer to the point of becoming a
controlled psychic exorcism with all of his experiences, fears, and desires
gushing out, usually between the words. It can feel like the writer is
sitting in a room and directly addressing you, offering universal truths
without being didactic, and we revere writers who can reach that level. Why
can't a movie be the same? Must film be an irreparably schizo medium?
What's between the words in Hitchcock?

At least that's the impression that I get from 'The 400 Blows.' I think
Truffaut may have said as much somewhere.

And you know how those Frenchies love their 'theories.'

The problem is that film is made with a dark room full of people in mind
(you all). Novels are conceived in terms of the reader, an individual (you).
Film is experienced collectively, the novel personally. It's public rather
than private speech, with about a dozen authors at that! And public speech,
for better and worse, can never be as nakedly honest as private speech.
People are always more guarded and self-conscious -- rhetorical -- speaking
to a crowd, and a crowd has a psychology and set of responses all its own.

The power of film is its mass hypnotic effect, somewhat like Hitler's
speeches. It makes us feel part of something larger, and closer to the other
people viewing. You're an emotional hostage. Because of that it's probably
the most politically powerful medium: think of how much 20th century
totalitarianism invested in it.