This weekend I watched “The Butterfly Effect” on DVD, and I must admit thinking it was underrated. I might feel differently if I had paid to see it in the theater, but as a rental it was definitely worth the price. It was one of the better takes on time-travel-induced alternate realities I’ve seen. I had only one serious complaint with the movie: its title. WARNING: Spoilers ahead.
Chaos theorists use the term “butterfly effect” as shorthand for the phenomenon of sensitive dependence on initial conditions. The notion is that small, seemingly insignificant events – something as tiny as the flapping of a butterfly’s wings – can result in cumulative changes culminating in drastically different outcomes, such as the creation of typhoons.
I would expect a movie titled “The Butterfly Effect” to draw on that insight, perhaps by having the time-traveling character step on a roach and thereby alter the outcome of presidential elections. But every history-changing event in this movie is undoubtedly of major significance, at least to the lives of the main characters: saving a little girl from molestation by her pedophile father, preventing a mother and her baby from getting killed in an explosion, and so on. These historical alterations change the present, not always for the better, but certainly in ways that follow straightforwardly enough from the historical events in question. Meanwhile, lots of insignificant details about the present remain essentially the same; for instance, Ashton Kutcher’s character always attends the same college, and even winds up in the same dorm room in at least three alternate realities. And at one point, Kutcher's character makes what could be a relatively major change in his life's history, with no apparent impact on the present except the sudden appearance of scars on his hands. Some changes, it seems, don't matter that much.
None of this makes the movie less worthwhile – it just makes the title inappropriate, and all the scientific commentary included in the DVD’s extras pointless and pretentious. If you’re looking for a better fictional treatment of the butterfly effect, watch Run Lola Run or The Simpsons: Treehouse of Horror V.