Stephen Hawking and Leonard Mlodinow's kicked off their new book: The Grand Design, with an book excerpt in the WSJ today:
Newton believed that our strangely habitable solar system did not “arise out of chaos by the mere laws of nature.” Instead, he maintained that the order in the universe was “created by God at first and conserved by him to this Day in the same state and condition.” The discovery recently of the extreme fine-tuning of so many laws of nature could lead some back to the idea that this grand design is the work of some grand Designer. Yet the latest advances in cosmology explain why the laws of the universe seem tailor-made for humans, without the need for a benevolent creator.
Many improbable occurrences conspired to create Earth's human-friendly design, and they would indeed be puzzling if ours were the only solar system in the universe. But today we know of hundreds of other solar systems, and few doubt that there exist countless more among the billions of stars in our galaxy. Planets of all sorts exist, and obviously, when the beings on a planet that supports life examine the world around them, they are bound to find that their environment satisfies the conditions they require to exist.
The weak anthropic principle is not very controversial. But there is a stronger form that is regarded with disdain among some physicists. The strong anthropic principle suggests that the fact that we exist imposes constraints, not just on our environment, but on the possible form and content of the laws of nature themselves.
Many people would like us to use these coincidences as evidence of the work of God. The idea that the universe was designed to accommodate mankind appears in theologies and mythologies dating from thousands of years ago. In Western culture the Old Testament contains the idea of providential design, but the traditional Christian viewpoint was also greatly influenced by Aristotle, who believed “in an intelligent natural world that functions according to some deliberate design.”
That is not the answer of modern science. As recent advances in cosmology suggest, the laws of gravity and quantum theory allow universes to appear spontaneously from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.
Our universe seems to be one of many, each with different laws. That multiverse idea is not a notion invented to account for the miracle of fine tuning. It is a consequence predicted by many theories in modern cosmology. If it is true it reduces the strong anthropic principle to the weak one, putting the fine tunings of physical law on the same footing as the environmental factors, for it means that our cosmic habitat—now the entire observable universe—is just one of many.
Each universe has many possible histories and many possible states. Only a very few would allow creatures like us to exist. Although we are puny and insignificant on the scale of the cosmos, this makes us in a sense the lords of creation.
Mlodinow is the author of The Drunkard's Walk: How Randomness Rules Our Lives — a must read according to other Farnam Street readers.