Roberta Sparrow wrote a book about time travel in the movie "Donnie Darko". This old lady explains in the book about how she thinks it works.
Donnie Darko is a time travel
movie. It involves a young man who is believed to be insane. This man
"Donnie" is taking medication which is later revealed to be
a placebo. In fact, Donnie Darko is like a saviour who sacrifices his
life so that his universe can live.
Therefore, Donnie Darko uses time travel to restore the universe.
Does it make sense?
Philosophy of Time Travel Roberta Sparrow is not whow it works. Time travel works quite differently. Donnie Darko is a movie by people who do not understand time travel. There are many universes not just one and we live in a multiverse. The movie believes that time splits are bad, which is true, but in actually, time splits occur to stop the Grandfather Paradox.
The idea of the Grandfather Paradox is that you could go back in time and convince your grandfather not to marry your grandmother, thus you would not be born.
Donnie Darko by fixing the universe gives up his life. Poetic by not real...
I believe that "Faber est suae quisque fortunae" - everyman is the creator of his own fortune.