A Brief History of Time

A Brief History of Time

Sum over histories Term Analysis

Richard Feynman first came up with the idea that particles do not have one history, but rather have every possible history. This means scientists cannot say exactly how a particle traveled from A to B, but by calculating all the possible routes from A to B, they can find the most likely one.
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Sum over histories Term Timeline in A Brief History of Time

The timeline below shows where the term Sum over histories appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 4
Human Curiosity and Ingenuity Theme Icon
Richard Feynman created the sum over histories theory to explain this. A particle is said to travel from A to B by... (full context)
Chapter 7
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...singularities, and Hawking’s work turned in that direction in the late 70s, focusing on Feynman’s sum over histories . (full context)
Chapter 8
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
...consistent theory that combines quantum theory and gravity. If there were, it should involve Feynmann’s sum over histories proposal, which states particles move from A to B by every possible path. Scientists know... (full context)
Human Curiosity and Ingenuity Theme Icon
To calculate sum over histories , one must use imaginary time, that is, imaginary numbers to represent time, which clears... (full context)
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
...mechanics and general relativity is that gravity is represented in a curved space-time. Applying the sum over histories to Einstein’s ideas on gravity, the history of a particle is a complete curved space-time... (full context)
Human Curiosity and Ingenuity Theme Icon
Each sum over histories history offers a comprehensive account of space-time and its contents. Again, the anthropic principle can... (full context)
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By applying the sum over histories and no boundary theory, one can find which characteristics of the universe are likely to... (full context)
Chapter 10
Human Curiosity and Ingenuity Theme Icon
...time travelers going back into alternative pasts, with total free will. This sounds like Feynman’s sum over histories , which states the universe had every possible history. But, each history would be self... (full context)
Human Curiosity and Ingenuity Theme Icon
Feynman’s sum over histories allows time travel on a miniscule scale. As particles follow the C, P, and T... (full context)