I think that Inception is all a dream-from the beginning of the movie to the end. My last blog, and the first section of my latest book-Inception and Philosophy: Because It's Never Just a Dream (published by Wiley/Blackwell)-presents this argument in detail. But the truth is we can't tell for sure. Any clue or piece of evidence can be interpreted multiple ways, and there is no guarantee that the most charitable interpretation of the film is the right one.
However, there is something else we can't tell for sure-whether or not we are dreaming...right now, this very moment.
This is a classic philosophical problem, first hinted at by Plato but most clearly articulated by Descartes. You may feel certain that you are not dreaming right now, but you have been just as certain that you are not dreaming while you have been dreaming! (We've all had that dream that we were so certain was real.) Thus we can't use our own subjective feeling that we are not dreaming as evidence that we are not-but what else could settle it? Although many philosophers have tried to solve this problem, all have failed. One cannot be certain that one is not dreaming; in fact, it seems that one cannot even know.
But I think the more interesting problem is this: how should we deal with this uncertainty? The fact that you can't know that you are not dreaming-that the world around you may not be real-creates a certain kind of angst. Perhaps you feel it right now. How should you deal with that angst?
You could choose to dismiss the problem, convincing yourself that you don't care whether you are dreaming. "What does it matter anyway? Dreams are still experiences, and all that matters is experience, right?" This is why Mal locked away her totem, the top, in the safe of her subconscious-so she would forget that Limbo was actually a dream. Limbo was her perfect world; why would she want to know it wasn't real? But there is something pitiful about someone who is fooled into believing something false, like the prisoners in Plato's cave staring at the wall thinking the shadows are real. There is something intrinsically valuable about having true belief, and knowing the way the world is. So you should care whether or not you are dreaming.
How else might one deal with this angst? The philosopher David Hume dealt with the angst in the same way that Cobb does at the end of the film. Hume realized that when he engaged in the everyday activities he enjoyed-for Hume, it was a game of backgammon, a conversation, and being "merry" with his friends-he forgot all about his skeptical worries; and when he returned to those worries they seemed so cold, strained and ridiculous that his angst was gone. Likewise, a the end of the film, worried that he is still dreaming, Cobb spins his top-only to be distracted by his children and leave his top behind. His children divert him and he is no longer worried. Like Hume, the important matters of everyday life have relieved his angst. As Christopher Nolan himself said, ""The important thing is that Cobb's not looking at the top. He doesn't care." One might assume that after spending time with his kids, Cobb's worry that he is dreaming will seem silly to him.
But for those of us who really are philosophically minded, we can't help but return to the problem now and again and feel that angst return. As Katherine Tullman suggests in the fifth chapter of my book, it may be that the only way one can truly alleviate that angst it to take "a leap of faith"-that is, to assume without proof or evidence that one is not dreaming and the world is real. Such leaps of faith are common in Inception, and the phrase is used many times. Cobb, for example, takes a leap of faith when he believes that Satio can deliver on his promise to have the charges against Cobb dropped. But leaps of faith can't always be good-after all, Mal took one right out of a window.
So when is a leap of faith a good thing, and when is it not? It is so that question I will turn next.