Book Review: A Brief History of Time

Title
A Brief History of Time

Author
Stephen Hawking

Date of Publication
1988 (original version)
1996 (updated version)

Reason for reading
An increased interest in physics lately, partially spurred on by discussion with you guys, and the lack of knowledge I have in comparison, but mostly spurred on just because the little I’ve read of the topic lately has interested me far more than it did while I was in college (unfortunately).

Synopsis
Hawking gives a great introduction to many concepts of physics that are normally beyond the scope of normal people (without spending a significant amount of time investigating it), and makes them easily understandable to the relative layman reading the book, dealing with many topics, including the expanding universe, the arrow of time, Heisenberg’s Uncertainty Principle, scientific determinism, black holes, wormholes, unification theory, and other things.

Review
As I mentioned to Brent, this is one of the best books I’ve ever read, at least in terms of science topics outside the realm of the traditional textbook. I specifically enjoyed the sections on the expanding universe and black holes, as I didn’t know the details of how it’s known that the universe is expanding, nor why it must be, and as for the latter, I only had a vague grasp on what black holes even were. Now I have a fairly solid understanding of both (and hopefully I’ll follow up to reinforce that learning instead of forgetting it). Also, he mentions God fairly regularly throughout the book, and what I liked is that he didn’t really take a side and ridicule the other (as a Dawkins might). Instead, he just brings it up and essentially discusses the options as if it were a regular scientific point to discuss.

Quotes
“The eventual goal of science is to provide a single theory that describes the whole universe. However, the approach most scientists actually follow is to separate the problem into two parts. First, there are the laws that tell us how the universe changes with time. (If we know what the universe is like at any one time, these physical laws tell us how it will look at any later time.) Second, there is the question of the initial state of the universe. Some people feel that science should be concerned with only the first part; they regard the question of the initial situation as a matter of metaphysics or religion. They would say that God, being omnipotent, could have started the universe off any way he wanted. That may be so, but in that case he also could have made it develop in a completely arbitrary way. Yet it appears that he chose to make it evolve in a very regular way according to certain laws. It therefore seems equally reasonable to suppose that there are also laws governing the initial state.” (11)
-this I thought interesting mainly for the 1st part dealing with the eventual goal of science.

“The final result was a joint paper by Penrose and myself in 1970, which at last proved that there must have been a big bang singularity provided only that general relativity is correct and the universe contains as much matter as we observe. There was a lot of opposition to our work, partly from the Russians because of their Marxist belief in scientific determinism, and partly from people who felt that the whole idea of singularities was repugnant and spoiled the beauty of Einstein’s theory. However, one cannot really argue with a mathematical theorem. So in the end our work became generally accepted and nowadays nearly everyone assumes that the universe started with a big bang singularity. It is perhaps ironic that, having changed my mind, I am now trying to convince other physicists that there was in fact no singularity at the beginning of the universe-as we shall see later, it can disappear once quantum effects are taken into account.” (53)
-this I found interesting because I’m very curious about both how scientific determinism fits into Marxism, and also because of the second part, with him arguing against his original theory. I just wonder if he has another mathematical theorem that disproves the original one, and if so, why couldn’t that be used as an argument to his original mathematical theorem, as he claims you can’t do.

“In effect, we have redefined the task of science to be the discovery of laws that will enable us to predict events up to the limits set by the uncertainty principle. The question remains, however: how or why were the laws and the initial state of the universe chosen?” (189)

“Up to now, most scientists have been too occupied with the development of new theories that describe what the universe is to ask the question why. On the other hand, the people whose business it is to ask why, the philosophers, have not been able to keep up with the advance of scientific theories. In the eighteenth century, philosophers considered the whole of human knowledge, including science, to be their field and discussed questions such as: did the universe have a beginning? However, in the nineteenth and twentieth centuries, science became too technical and mathematical for the philosophers, or anyone else except a few specialists. Philosophers reduced the scope of their inquiries so much that Wittgenstein, the most famous philosopher of this century, said, “The sole remaining task for philosophy is the analysis of language.” What a comedown from the great tradition of philosophy from Aristotle to Kant!” (190-91)
-This I thought interesting due to the fact that Brent loves Noam Chomsky, and he’s a linguist, which according to Wittgenstein is the sole remaining task of philosophy (or was at the time). But another interesting point is that while in a Barnes & Noble in Minnesota, I glanced through a book on the 100 most influential scientists, and on the list saw Noam Chomsky (rather high, I think at ~31). So where does linguistics fit?

Questions
-On page 72, Hawking notes that gravity is unique of the four forces in that it is the only one that acts over large distance, and also is only attractive. What is unique about gravity that makes it only attractive, and is it possible that it could also be repulsive, but that hasn’t been discovered yet? I’m sure there’s a simple answer to this question, I’m just curious what it is. I have a tremendous list of questions I didn’t understand. I just thought this was a decent one to put up since you guys might know and if so, might be able to easily relay the answer.

Further Reading
God Created the Integers
Stephen Hawking
2007

The Elegant Universe
Brian Greene
2000