'Inception': 9 Surprising Sleep Facts From the Movie

"Am I a man dreaming I'm a butterfly, or a butterfly dreaming I'm a man?" Chuang Tzu asked 2,300 years ago. In Christopher Nolan's stylish sleep thriller "Inception" he answers we're both -- butterfly and man.

Yet the science behind Inception is more surreal than the film, whose lovingly layered plot still underplays the wonderfully weird wildness of dreams. So, dream thief Mr. Cobb, what about your job is science fiction and what's science?

(Spoiler alert: plot elements are revealed)

Is Time Altered In Our Dreams?

Does time speed up in dreams so that 10 minutes "outside" becomes an hour during the dream? Yes, but not like in the movie, where time geometrically and precisely expands with the dream's depth. We can do far more. In real dreams infinite time may occur within seconds of "outside" time.

What Kinds Of Dream States Occur In Inception?

Not much you or I might recognize. In Inception, people are immediately sedated into designer dreams that appear to be REM sleep. However, virtually all present-day sedatives suppress REM, while Inception's designer drugs also negate real REM effects.

Is Constructing Dreams Out Of One's Memories Dangerous?

No, just necessary. REM sleep is a critical driver of brain development, and literally rebuilds the brain. As movie plots are constructed out of old movies, so does REM and other stages of sleep remix new information with old memories, forming a huge part of our identity. Just like in science fiction movies, we wake up each morning with different memories than the person who went to sleep.

Do The Layer After Layer Of Dreams Seen In Inception Happen In Normal People?

Yes. It is not uncommon for people to dream themselves inside another dream. In fact, sorting it out may become as complicated as understanding Inception's plot.

Can Someone Enter Into Another's Dream And Change It?

Scientifically, no. Not even close, unless you're a Tibetan dream yogi or the local shaman.

Is It Impossible To Place Content Into Someone Else's Dream?

No. This happens all the time -- consciously. Lucid dreamers do it with great relish, and I'll show you a way you can do it, too, at the end of this piece.

Can People Become Addicted To Their Dreams?

Can people become addicted to their dreams? The answer is no, athough some psychotics and a few political commentators can't tell the difference between dreams and reality.

Are The Matrix-esque Scenes Of Negating Gravity Realistic?

Yes. In REM dreams, position sense gets turned off, and we can and do go anywhere in space and time -- one reason 99 percent of people fly in their dreams.

Can The Lucid Dreaming Heroes Of "Inception" Take Over The Dreams Of Others?

No. However, they can take over and control their own. In fact, director-writer Nolan has been lucid dreaming since he was 16.

What Can You Do With Your Dreams?

Plenty -- you can pre-dream. Try this:
1. Write down an old, favorite dream or experience in three to four sentences.
2. Add two sentences that remake that dream's plot you the way you want.
3. Visualize the new dream three to four times a day a minute each time.
4. When you wake, record your dreams.