In the science-fiction movie Inception, Leonardo DiCaprio plays Dom Cobb, an expert at entering other people’s dreams, often for the purpose of corporate espionage. One aspect of dreaming as portrayed in the movie is the alteration of the passage of time: One minute of time spent dreaming equals 12 minutes experienced.

One unexplored aspect of this effect is that it could be seen as a method of radical life extension. This factor of experiencing 12 times more life lived than one would in the waking world is already a pretty radical extension of life experienced. In fact, the character Yusuf, a master pharmacologist/chemist, has a clientele of people who meet up each day to share their dream state. In a setting that eerily echoes an opium den, these people come each day not, as their caretaker puts it, to dream, but to wake up. Their dreams have become their lives.

Yusuf has also created a concoction dreaming that increases the time-altering effect of dreaming, raising the multiple to a factor of 20.

The effect is compounded by going into dreams within the dreams; when the dreamers get to the third level -- a dream within a dream within a dream, the character Ariadne realizes that on the 10-hour transpacific flight they are planning will take an astonishing 10 years.

Ten years of life in a 10-hour dream? Anyone who wished to maximize the amount of life they experience would sign on.

It goes further. At the bottom level of dreaming is a level called Limbo. Limbo is unstructured dreamspace, in which dreamers can create and shape whatever they wish. Cobb and his now-deceased wife spent a nap in Limbo, and they created a world of their own, populated with their memories and creations; they lived there and grew old together before they awoke.

So if the rules of Inception applied, and one managed to drop into Limbo, one could conceivably live a long life, with superhuman control over the reality of the dreamworld, and grow old many, many times. Were this the case, I think many people would sign up for at least some time experiencing the time-dilating properties of at least some level of controlled dreaming.