Quotes from ‘A brief history of Time’ by Stephen Hawking

The review for the book

These are excerpts from the book. They are slightly long because I just couldn’t understand what not to include, it was all so deeply related! I have added my own comments to explain the context and to tell you why I liked a particular excerpt.

As we shall see, the concept of time has no meaning before the beginning of the universe. This was first pointed out by St. Augustine. When asked: “What did God do before he created the universe?” Augustine didn’t reply: “He was preparing Hell for people who asked such questions.” Instead, he said that time was a property of the universe that God created, and that time did not exist before the beginning of the universe.

Hawking is probably an atheist. Yet, here he praises St. Augustine for being able to grasp that time may not have any meaning outside of the universe, the reason for his conclusion notwithstanding. He also makes a subtle remark about how we have regressed from discussing ideas to damning each other in foolish attempts of one-upmanship.

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.

A lot of people don’t understand the concept of a theory and how we can never really be sure that we are right, and that we can only be sure that we are wrong! Here, Hawking takes time to explain it in very simple terms. Another favorite person of mine, Richard Feynman, does this with a lot more flamboyance –

The discovery of a complete unified theory, therefore, may not aid the survival of our species. It may not even affect our life-style. But ever since the dawn of civilization, people have not been content to see events as unconnected and inexplicable. They have craved an understanding of the underlying order in the world. Today we still yearn to know why we are here and where we came from. Humanity’s deepest desire for knowledge is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in.

This is what I read – Everything is pointless. But we are still awesome :)

Bishop Berkeley, a philosopher, believed that all material objects and space and time are an illusion. When the famous Dr. Johnson was told of Berkeley’s opinion, he cried, “I refute it thus!” and stubbed his toe on a large stone.

One of the many interesting anecdotes that are sprinkled throughout the book.

Between 1887 and 1905 there were several attempts, most notably by the Dutch physicist Hendrik Lorentz, to explain the result of the Michelson-Morley experiment in terms of objects contracting and clocks slowing down when they moved through the ether. However, in a famous paper in 1905, a hitherto unknown clerk in the Swiss patent office, Albert Einstein, pointed out that the whole idea of an ether was unnecessary, providing one was willing to abandon the idea of absolute time.

This is how he introduces Einstein. You are furiously reading through a bunch of revolutionary ideas in physics that are becoming difficult for scientists to support and explain. When suddenly, you read about this random clerk from Germany who changes everything with his fresh perspective. Then it hits you that it was Albert Einstein and you understand why he is considered to be the greatest scientist of the century.

In the following decades this new understanding of space and time was to revolutionize our view of the universe. The old idea of an essentially unchanging universe that could have existed, and could continue to exist, forever was replaced by the notion of a dynamic, expanding universe that seemed to have begun a finite time ago, and that might end at a finite time in the future. That revolution forms the subject of the next chapter. And years later, it was also to be the starting point for my work in theoretical physics. Roger Penrose and I showed that Einstein’s general theory of relativity implied that the universe must have a beginning and, possibly, an end.

Yes, Hawking along with Penrose was the one who put an end to the whole ‘Universe has always existed and will continue to exist’ argument. How does he tell of that momentous achievement? He just mentions it. If it were up to him, I believe he would have made it a footnote.

Only one man, it seems, was willing to take general relativity at face value, and while Einstein and other physicists were looking for ways of avoiding general relativity’s prediction of a non-static universe, the Russian physicist and mathematician Alexander Friedmann instead set about explaining it.

This shows why it is so amazing to hear a first person account of something. Hawking was there when our understanding of the universe was changing and he was a part of the inner circle of the people who were bringing about that change. In this book, he talks about many such unknown and unsung heroes who made singular contributions to the field, but were sadly forgotten.

If time travel is possible, where are the tourists from the future?
NOTE: There are more quotes that I would like to include, but they are long and I have a hard copy, so I have to type it out. So, I will add them as and when I get the time.

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