“If time travel is possible, where are the tourists from the future?”
Source: A Brief History of Time
Stephen Hawking: Quotes about time
Stephen Hawking was British theoretical physicist, cosmologist, and author. Explore interesting quotes on time.
Stephen Hawking:
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Source: A Brief History of Time (1988), Ch. 1
Context: 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.
“Only time(whatever that may be) will tell.”
Source: A Brief History of Time
Source: A Brief History of Time (1988), Ch. 1
Context: 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.
Into The Universe with Stephen Hawking (2010)
“Disorder increases with time because we measure time in the direction in which disorder increases.”
Source: A Brief History of Time (1988), Ch. 9
Context: Just like a computer, we must remember things in the order in which entropy increases. This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. You can’t have a safer bet than that!
with G.F.R. Ellis, "The Large Scale Structure of Space-Time" (1973) Preface
Heard in person by this contributor when Hawking showed-up in a Caltech physics class taught by Robert Christy in 1980 or '81; when asked about collapse of the state-vector he whispered to his assistant Chris (surname unknown) something at which point Chris stood up and said 'Stephen is paraphrasing Herman Göring by saying "When I hear the words 'Schrödinger's Cat' I reach for my gun."'.
Source: In a conversation with Timothy Ferris (4 April 1983), as quoted in The Whole Shebang (1998) by Timothy Ferris, p. 345 http://books.google.com/books?id=qjYbQ7EBAKwC&lpg=PA345&ots=F6VWymjiPx&dq=%22reach%20for%20my%20revolver%22%20hawking%20-%22oft-made%22&pg=PA345#v=onepage&q=%22reach%20for%20my%20revolver%22%20hawking%20-%22oft-made%22&f=false
Last lines. Hawking later wrote: "In the proof stage I nearly cut the last sentence in the book... Had I done so, the sales might have been halved.
Black Holes and Baby Universes and Other Essays (1993)
As quoted in "Return of the time lord" in The Guardian (27 September 2005)
The Beginning of Time (1996)
http://www.reclaimingthemind.org/blog/2013/09/stephen-hawking-detained-in-russia-for-bible-smuggling/