Saturday, November 22, 2014

The Grand Design by Stephen Hawking (Book Review #111 of 2014)


The Grand Design
I read this book (published 2010) immediately after reading The Universe in a Nutshell (2001). I read Black Holes and Baby Universes a few years ago. I have read Brian Greene's works, so felt rather up-to-date on where quantum physics was at. I found this book to be more accessible than Greene's work, and a more interesting read than Nutshell since Hawking is contemplating theoretical physics' meaning for philosophy. That philosophical bent is a real problem for physics since the scientific method, which Hawking holds favorably in The Grand Design, requires hypothesis testing. For more on these problems, and a large criticism of Hawking I plan to read Lee Smolin's The Trouble with Physics.

The author begins by stating that philosophy has not kept up with science, particularly modern physics. Hawking gives a brief history of science with an emphasis on physics and a look at how philosophy looking at science developed from Aristotle (rejected atoms b/c soulless) to Descartes (believed that the body was machine governed by laws, but the soul was not) to Newton (discovered many laws of the universe but held that God was free to intervene against them).

If there are natural laws, can/does God violate them to perform miracles? That's an important question, as is the question of free will and determinism. Where does free will come from? If physicists nail down a Theory of Everything, will everything be deterministic henceforth?

Hawking writes the laws of (this) universe arose from the big bang, and lengthily establishes what those laws are. But the universe has an infinite number of histories and contingencies. Wrap your head around this:
"the probability amplitude that the universe is now in a particular state is arrived at by adding up the contributions from all the histories that satisfy the no-boundary condition and end in the state in question. In cosmology, in other words, one shouldn't follow the history of the universe from the bottom up because that assumes there's a single history, with a well-defined starting point and evolution. Instead, one should trace the histories from the top down, backward from the present time...The histories that contribute to the Feynman sum don't have an independent existence, but depend on what is being measured. We create history by our observation, rather than our history creating us...histories in which the moon is made of cheese do not contribute to the present state of our universe, though they might contribute to others. That might sound like science fiction, but it isn't."

Hawking explains M-theory, p-branes, and other developments in quantum physics. The last pages of the book are the most important as Hawking contends that M theory explains how a universe can arise from nothing. But it does not lead to determinism in the sense that it would be mathematically impossible to calculate the movements of any one being. So, a theory of everything that is not what Hawking desired to find in Black Holes and Baby Universes.

This book seems much more consequential than Nutshell. I found it more entertaining and thought-provoking throughout. For now, 4.5 stars out of 5.

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