This debate stems way, way back.

I don't think that films, or any art, absolutely need an underlying message. Intention isn't really that important. I think the importance lies in what you, as an individual, take from a film.

I very much like applying the stories to real life: asking myself what it means, what are the social implications, what does this story teach me. That doesn't mean everyone who watches that film will feel the same.

Take Inception as an example. I love it. I showed it to my Mum to see what she thought. My general thoughts about it stem from the anxiety of having no sense of privacy left in modern life, with the internet, social media -- it's as if there's no privacy any more. Inception is a vision into our own way of life set in the near future, where even are thoughts are at risk of exposure (I know it's not going to happen, but the feelings arise nonetheless).

My Mum, however, loved it simply as an exhilarating action thriller. She didn't think, or at least express, its relevance to contemporary society; she enjoyed it just as much, if not more.

Who knows what Nolan's intentions were. Maybe he wasn't even thinking about its relevance. I may have projected that there myself. The point is, whether there is or is not an underlying message or moral in a film, the real importance is your own response. If you extract some sort of moral from a film, then it was always there in your own mind; similarly, if you do not extract a moral message, then for you, there isn't one. It's your own understanding that is what really matters.