The lighthouse acts as a symbol throughout the novel of different and competing versions of reality that are created through the passing of the years, emotions or subjective experience. This is shown most clearly in Chapter VIII, when James, on the Ramsay's boat that is approaching the lighthouse, reflects on the different images he has of the lighthouse in his mind. Note what he ponders:
The Lighthouse was then a silvery, misty-looking tower with a yellow eye, that opened suddenly, and softly in the evening. Now—
James looked at the Lighthouse. He could see the white-washed rocks; the tower, stark and straight; he could see that it was barred with black and white; he could see windows in it; he could even see washing spread on the rocks to dry. So that was the Lighthouse, was it?
No, the other was also the Lighthouse. For nothing was simply one thing. The other Lighthouse was true too.
He deliberately remembers the memories of the lighthouse thathe has a child, when it assumed an important place in his imagination, becoming a "misty-looking tower with a yellow eye." Now, however, the lighthouse appears practical and functional and nothing to excite the imagination. As he decides about which "version" of the lighthouse is actually real, he realises that this is the wrong question to asks, as both lighthouses are actually "true," even though they are so different from each other. What James has to do is to allow both of these contradictory images to be reconciled into one unifying truth. This is the challenge that faces the characters in this novel, and the reader, as to admit the contradictory nature of all things and to reconcile those differences is to enjoy a richer understanding of life.