Gaiman really likes to explore the idea of time and it's impact on people in two ways: The first is showing how the passage of time takes a toll on all that is beautiful and pure. Children unfortunately have to turn into adults; quaint countryside villages inevitably turn into cookie-cutter home developments; and over time our memories fade into blurry nonexistence.
The second way he uses it in The Ocean at the End of the Lane is to explore what would happen if we were less beholden to the laws of time. What if we could live long enough to see the moon being created? What would we be like if thousands of years could pass and we still looked like we were eleven years old? These are big questions, and they beg us to examine the role of time in our own lives.
Questions About Time
Do you think Lettie has a choice about what age she is? She's been "eleven" for hundreds of years—did she pick that age to portray? Or does she just age ridiculously slowly?
If we remove the prologue and epilogue from the book, how does the story change? What do we gain from reading about the whole thing decades later, through his adult eyes?
What impact has time had on the boy's childhood home and neighborhood?
The Hempstock women seem to operate outside of normal time parameters. What are some of the advantages and disadvantages of this?
Chew on This
Gaiman likes to glorify the state of childhood. He views the process of growing older—and the passage of time—as one of loss and disappointment.
Time and memory are inextricably linked, such that by altering memory you are altering time, and vice versa.