Time is approached subjectively by both Woolf and her characters in To the Lighthouse.
Western, rationalist thought has divided time neatly into tiny packets that are theoretically and even measurably the same: every minute is comprised of the same sixty seconds, and every hour of the same sixty minutes. However, the characters in the novel experience time very differently. Woolf, in the novel, is trying to explode the rationalist notion of time and say that, in reality, we don't experience our lives in such a way that every "packet" of time is the equivalent of another. Instead, as she writes in other places, we have "moments of being." Much of what of what we experience passes over us without being remembered: for example, in other writing, she uses her own childhood, where the monotony of being taken to the park for a walk every afternoon meant that her memory of those walks is utterly indistinct—most of that time is forgotten. However, in contrast, in moments of being, time seems to stand still and stretch out, and the memories of these times become etched on us in great detail.
The first and longest part of the book, which comprises only a day is told often, though not entirely, through the consciousness of Mrs. Ramsey, is meant as a moment of being. Details are etched on us, and time is elongated. We learn much of what Mrs. Ramsey is thinking as she carries out a dinner party that is a success—though not without threats of disaster—from the conversation to the arrangement of the fruit at the center of the table. Time is elongated through the repetition of the poetry that floats through her mind: for example, “And all the lives we ever lived and all the lives to be are full of trees and changing leaves.” This quote itself challenges rationalist notions of time.
The day at the Ramsey summer house on the Isle of Skye may seem trivial, but it is of such events that lives—especially women's lives—are made, Woolf is saying. Such is the texture of life. Let us hang onto it.
Later, time collapses, and ten years—including the all important event on the world stage, World War I—pass in just a few pages, showing how vast swathes of time can seem to go by rapidly, just as a day can seem to last eons. In the third section of the book, where the children and their father finally travel to the lighthouse, we are back to a slowed and elongated passage of time.
The novel attempts to show how time is experienced by people in lived, subjective reality rather than what science tells us time is.