We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
In Rovelli's scheme, a clock's hands do not point upright because the universe says it is 12 o'clock; they point upright because of the location of the pendulum. Therefore the notion of time is meaningful only in a small range of physical situations in the universe, such as human experience. In most cases, however, time is meaningless. "In general, there is no time at all," Rovelli says.
Though this approach might seem radical, many researchers share Rovelli's sentiments. For example, Harvey Brown, an expert on scientific interpretations of reality from the University of Oxford, has argued that we "construct" time from the physical properties of the things around us.
Newton and Leibniz debated this very point. Newton portrayed space and time as existing independently, while Rovelli and Brown share Leibniz's view that time and space exist only as properties of things and the relationships between them.
It is still not clear who is right, says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter. If the central property of space-time is the result of the existence of matter, how can we be sure that space and time exist on their own and are not convenient illusions? "Hence my hesitation," Norton says.
How can we be sure that time and space exist on their own and are not convenient illusions?
I suspect that only the present exists, and that time is a property of matter, and not a thing in itself. Words are symbols, and just a pale reflection of reality. Including the word "reality." But what do I know? And, by the way, what time is it?
More importantly, re Time - how many shopping days 'til Christmas? I do not shop. Except for guns.
" ... the consensus seems to be that space and time exist on their own..." Well, today maybe, to those physics guys. But not to each of us.
As Sir Walter Raleigh said, written the night before his death ...
"Even such is Time which takes in trust
Our youth, our joys, and all we have,
And pays us but with age and dust,
Who in the dark and silent grave
When we have wandered all our ways
Shuts up the story of our days.
And from which earth, and grave, and dust,
The Lord shall raise me up, I trust."
I like Meta's idea of Time as a river, on whose back we ride for awhile... Until we don't.
Possibly the river can flow in opposite directions at different times, as the Nile does.
Time is a mental construct. the past is memory and the future is immagination. Change is real. We can relate the rate of change in one object to the rate of change in other objects ie the sun, moon and stars and we have time or a means to discribe change. JP
Geez, The New Scientist, why not cite a real publication? And no physicists cited -- Rovelli doesn't count -- just a couple of philosophers? And the bit about relativity is BS, time enters into the equations in a fundamentally different way than space does, the signature of the metric is (1, -1, -1, -1). Note the different sign for the time component. Calling in Leibniz is a red herring, (special) relativity came from Maxwell's equations and electrodynamics, not a study of Leibniz. It's not as if Liebniz did anything useful in physics.
One does get tired of the constant stream of publicity that flows from the LQG folks. They can't manage to compute anything, so they propagandize and try to set themselves up as the priests of the post-modern "socialist" physics.