Far out cosmology: does time really exist? (Introduction)

by David Turell , Saturday, April 23, 2022, 00:07 (734 days ago) @ David Turell

This book says no:

http://www.sci-news.com/physics/timelessness-10738.html?utm_source=feedburner&utm_m...

"Physicists want to produce a theory of ‘quantum gravity’ that replaces general relativity and quantum mechanics, while capturing the extraordinary success of both. Such a theory would explain how gravity’s big picture works at the miniature scale of particles.

"It turns out that producing a theory of quantum gravity is extraordinarily difficult.

"One attempt to overcome the conflict between the two theories is string theory. String theory replaces particles with strings vibrating in as many as 11 dimensions.

"However, string theory faces a further difficulty. String theories provide a range of models that describe a Universe broadly like our own, and they don’t really make any clear predictions that can be tested by experiments to figure out which model is the right one.

"In the 1980s and 1990s, many physicists became dissatisfied with string theory and came up with a range of new mathematical approaches to quantum gravity.

"One of the most prominent of these is loop quantum gravity, which proposes that the fabric of space and time is made of a network of extremely small discrete chunks, or ‘loops.’

"One of the remarkable aspects of loop quantum gravity is that it appears to eliminate time entirely.

"Loop quantum gravity is not alone in abolishing time: a number of other approaches also seem to remove time as a fundamental aspect of reality.

***

"...unless we can come up with a good account of how time emerges, it is not clear we can simply assume time exists.

Time might not exist at any level.

***

"While physics might eliminate time, it seems to leave causation intact: the sense in which one thing can bring about another.

"Perhaps what physics is telling us, then, is that causation and not time is the basic feature of our Universe.

"If that’s right, then agency can still survive. For it is possible to reconstruct a sense of agency entirely in causal terms.

"At least, that’s what Kristie Miller, Jonathan Tallant and I argue in our new book.

"We suggest the discovery that time does not exist may have no direct impact on our lives, even while it propels physics into a new era."

Comment. no surprising at all to me. Time only exists in the minds of observers, in our case, us. Cause and effect must always be present. Every effect has a cause. Therefore, there is a sequence of events at all times. but as humans we codify this into segments we call seconds, minutes, etc., based on the way we have divided up our day/night sequence from Earth's daily rotation. So how about old Einstein? No problem. We have his concept of a fabric of space with sequential cause and effect events and the relative view his observers have from their points of view. Still doesn't get us to one grand unified theory, but another Einstein may be in the wings in the future. Until then quantum mechanics will remain a puzzle. God doesn't explain why this crazy universe is so weird to us, but He doesn't have to, does He? I'll let dhw struggle with that. I don't have to.