Inception (Spoiler!)

[Cardinal]

I got into a discussion with someone about Inception today. She said that the point of the movie was whether or not the real world was in fact real, or a dream like his wife believed (even though it was Leonardo who subconsciously if unintentionally planted the idea himself). I argued that it was unknowable since there weren't enough clues in the film, and it didn't matter because that particular question was a red herring anyway: the purpose of wife in the plot was to show Leonardo's misery and his demons in having to go into the mission and, in the end, pull the Japanese man out of his own subconscious limbo. She didn't buy that, certain if she watches the movie again she'll pick up additional clues. What do you think?