What is the importance of "The Ant" in the novel, Love and Other Thought Experiments?

The author uses the ant as a motif throughout the novel to explore the possible existence of a divine presence. Just as every individual must decide if God exists or does not exist, every character in the novel must decide whether or not the ant is real. Without the ant, the characters have trouble rationalizing their existences, or the significance of coincidences in their lives.