Although the narrator of Lightman's story is never actually named, it's reasonable to guess he is the eponymous Mr g. And, given Mr g's abilities, it's a logical conclusion that Mr g is actually God. Mr g lives in the Void, where "Practically everything slept in an infinite torpor of potentiality," with his querulous Aunt Penelope and long-suffering Uncle Deva.
One day, Mr g wakes from a nap and decides to create the universe. He starts with the first necessary element: time.
"I had to chosen to replace nothingness with something. Something is not nothing. Something could be anything. My imagination reeled. From now on, there would be a future, a present, and a past. A past of nothingness, and then a future of something."From this point on, we're taken on a wonderful ride as Mr g contemplates, examines and assesses his next steps and their impact. He soon creates space, followed by (curiously) music, and then quantum physics.
It's at this point that he meets a traveling stranger whom he can't account for: Belhor and his grinning beasts, Baphomet the Larger and Baphomet the Smaller. They are anomalies outside of Mr g's sphere. As Mr g continues crafting the cosmos, he is continually visited by the mysterious Belhor, who challenges Mr g to think critically about the nature of his creation. Even as Mr g begins refining his worlds with rules meant to add order and logic and populating that space with matter, Belhor poses difficult questions of faith, free will, and relatively.
These existential exchanges are some of the best parts of the book. Mr g comes across as young, thoughtful and optimistic. His discussions with Belhor make him realize the enormity of his responsibility: He has set in motion a chain of events that eventually leads to the evolution of sentient organisms and human life. But what is the nature of life? Of consciousness?
Mr g must decide what role he will play in the lives his worlds have spawned — never suspecting that in the end, they will effect him just as much as he does them.
This is a story that melds together elements of religion, philosophy, math, science and ethics in an easily understood matter. God, in Lightman's tale, seems like a person just like you or me (except with infinite power) faced with the daunting prospect of creating something from nothing. But not just anything:
Life. Civilization. Meaning.