Stephen Hawking's latest book: The Grand Design left me quite disappointed. It was announced as a new approach to the classical question: Does (a) God exist? Hawking and co-author Leonard Mlodinow however turn around the pot and declare instead: God is not necessary for explaining the world and the creation to exist. They formulate their basic questions as follows:
Why is there something rather than nothing?
Why do we exist?
Why this particular set of (physical) laws and not some other?
Before however the authors come to answer these points in the last chapter on page 171 of their book the reader gets a flash course in old, modern and most recent physics, somewhat short for the layman to grasp but a good repetition for persons interested in the topic who have read this before. Luckily once in a while the authors like to be funny, e.g., when they explain symmetry that a flipped donut looks exactly the same, unless it has a chocolate topping, in which case it is better just to eat it or We have observed that the moon is not made of Roquefort cheese which is bad news for mice. These remarks have the advantage of keeping the reader alive.
Let us see how the authors tackle the answers to the questions posed above: Spontaneous creation of matter i.e. new worlds in fact can be explained in combining relativity theory and quantum mechanics within the space dimension of a Planck length. A Big Bang starting within the dimension of 10-35 meters can macroscopically nicely be illustrated with the appearance of micro bubbles in a boiling liquid where some of those will expand to form big vapor bubbles. Within this image time has an origin and the question of what was before time zero becomes meaningless. New universes are spontaneously created out of the energy of empty space due to quantum fluctuations. Only to say that Einstein disliked quantum mechanics as for him God doesn't throw dice.
The picture of micro bubbles in a boiling liquid can further be stretched: Only those micro bubbles, i.e., Big Bangs will expand into universes where the combination of physical constants and laws just fit each other. The world in which we live would not exist if constants like the gravitational constant, the speed of light, the electron radius etc. were not those they are. Varying the values of our known physical parameters just a few percent will lead to unstable universes, i.e., to worlds that cannot exist.
Remains the salient question: Why do we exist? In a first step also here the authors stress a mathematical model called the Game of Life where structures using energy and following defined laws reproduce themselves. Viruses do that, even the evolution to higher forms of life can be understood as complex systems of limited size that are stable and reproduce themselves. Darwin's selection principle fits nicely into this pattern. However the formation of life in the form of self-producing structures as they are known to us requires as necessary conditions water, oxygen and a friendly habitat with temperature variations remaining within certain limits just like mother earth provides. Living structures can and will react when stimulated within limits otherwise they will die.
This however does not explain why and when beings possess a free will. For the authors the behavior of a robot is predictable because it is calculable. When however a living being has more than about 1027 atoms, we would therefore have to say that any complex being has free will - not as a fundamental feature, but as an effective theory, an admission of our inability to do the calculations that would enable us to predict its actions. Nice try, but is the statement that because we are unable to calculate a structure the convincing evidence for the existence of a free will? And is it this free will that pushes us to believe or not believe in a somewhat reduced God, a God just throwing dice? There was this other approach exactly 40 years ago when Jacques Monod in his book: Le hazard et la nécessité denied us our free will. Monod suspected a genetic defect as the origin of man's quest for God, a fault that we according to him must overcome. Oh Lord, where in all this is the personal God that Jesus told us we shall call our Father!?
Hawking and Mlodinow summarize: Spontaneous creation is the reason there is something rather than nothing, why the universe exist, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going and The fact that we human beings - who are ourselves mere collections of fundamental particles of nature – have been able to come this close to an understanding of the laws governing us and our universe is a great triumph. But perhaps the true miracle is that abstract considerations of logic lead to a unique theory that predicts and describes a vast universe full of the amazing variety that we see.
Today I read in Murphy's Law Calendar: There are some things that are impossible to know - but it is impossible to know these things. Now I think I am more than ready to read Küng's book about what he believes!