Pentcho Valev

2017-11-29 08:03:47 UTC

Edward Witten: "I tend to assume that space-time and everything in it are in some sense emergent. By the way, you'll certainly find that that's what Wheeler expected in his essay. As you'll read, he thought the continuum was wrong in both physics and math. He did not think one's microscopic description of space-time should use a continuum of any kind - neither a continuum of space nor a continuum of time, nor even a continuum of real numbers. On the space and time, I'm sympathetic to that." https://www.quantamagazine.org/edward-witten-ponders-the-nature-of-reality-20171128/

My comment in Quanta:

"Emergent space-time" is a category mistake. Specetime has already emerged - it is a deductive consequence of Einstein's constant-speed-of-light postulate:

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime." http://community.bowdoin.edu/news/2015/04/professor-baumgarte-describes-100-years-of-gravity/

Anything deduced from different premises would fall in a different category and would have nothing to do with Einstein's spacetime - combining the two concepts would be absurd. For instance, bringing granularity to spacetime is equivalent to painting spacetime in yellow. If the original concept of spacetime is unacceptable and should be replaced, then the underlying premise, Einstein's constant-speed-of-light postulate, is false and should be abandoned. The step is unavoidable if logic is obeyed.

Pentcho Valev

My comment in Quanta:

"Emergent space-time" is a category mistake. Specetime has already emerged - it is a deductive consequence of Einstein's constant-speed-of-light postulate:

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime." http://community.bowdoin.edu/news/2015/04/professor-baumgarte-describes-100-years-of-gravity/

Anything deduced from different premises would fall in a different category and would have nothing to do with Einstein's spacetime - combining the two concepts would be absurd. For instance, bringing granularity to spacetime is equivalent to painting spacetime in yellow. If the original concept of spacetime is unacceptable and should be replaced, then the underlying premise, Einstein's constant-speed-of-light postulate, is false and should be abandoned. The step is unavoidable if logic is obeyed.

Pentcho Valev