Is time an illusion?
newscientist.com
newscientist.com
Is temperature an illusion? Certainly not. And yet, as the article says, it's merely a model of the interaction between molecules.
Some models explain more than other models. Models that explain more are better. Thinking in terms of real/illusion is not helpful at all.
No, the word "illusion" references an artifact that is both real and effective, yet whose true nature is misunderstood.
Moreover, for X to be an illusion, it necessarily must exist in some way.
You can't call something an illusion just because its true nature is misunderstood. An illusion is something that looks deceptively like something else. A hologram of a table is an illusion, but just misunderstanding the nature of a table (e.g. misunderstanding the fundamental particles from which it's constructed) does not make it an illusion.
Saying that time is an illusion is like saying that we appear to be living in a universe with time, but actually we don't. We are in fact experiencing something that looks like time, but isn't really time.
But obviously we do live in a universe with time, and the fact that time may turn out to be something strange or unexpected does not make it an illusion. It just means we misunderstood its true nature.
But the more I think about it, the more I realize that damn near everything we do of value relies on hard science. If you had me pick one post-agriculture profession to be my only formal profession in the world, it'd have to be engineering. Engineering creates tools that greatly expand the ability of everyone else to do what they're doing. And yet, without physics and chemistry, we're not engineering damn near anything of value. Behavioral and social sciences have made such huge leaps due to increased communication, mobility, and processing and storing of information. All that can be credited to some damn amazing engineers, who all needed math and hard science to build what they did. It makes me remember from time to time, that though I'm not a hard scientist and will likely never more than dabble in it, it's pretty damn amazing stuff, and ought to be regularly given a nod of appreciation to its amazingness.
Ernest Rutherford
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The "intriguing development" by Rovelli is that he used decoherence to explain measurement probabilities in some relativistic model. Time still exists in this model (which lives over R^{3+1}), but nothing happens instantaneously. Basically, he showed that the relativistic schrodinger equation gives the same experimental predictions as wave collapse.
I gave a talk last week on decoherence, just working out an explicit example where we can almost exactly solve the combined particle/measurement device system. The idea that wave collapse is unnecessary was not uncontroversial.
A quote from before I even gave the talk: "I don't believe you."
Well, Cramer (the one I cited) for one. David Mermin. Cerf and Adami. Roland Omnes. John Preskill. How many do you want?
> I gave a talk last week on decoherence
To what audience?
As for the physicists you cite, the ones I recognize seem to work on either quantum information or foundations of QM. Decoherence is far more accepted in these fields than in the rest of physics.
BTW, collapse is easily debunked: take a two-slit experiment a put a detector at one slit. Interference is destroyed for all photons despite the "fact" that only half the photons "actually" interact with the detector. Collapse cannot account for this. (I put "fact" and "actually" in scare quotes because in true fact all the photons interact with the detector, but not according to the collapse theory.)
It's very hard to describe time without using the word time: A series of events -- What's an event? The best one I have is: Why can't two object occupy the same space? Well, they can, but at different times. Not really an explanation, but I think it's a good illustration.
Isn't time sort of like goodness, so fundamental that it's indescribable with invoking itself?
If it's determined that the universe, and everything in it, lasts (in one form or another) forever, then the meaning of time disappears. You cannot have time unless you have a beginning and an end.
Nobody can prove the Big Bang theory without-a-doubt: we only could rise theories against it, or bring facts against it, but it will stay an unproven theory forever, very similar to math theories: you can't prove them without-a-doubt, you only can give it credit currently, and because there hasn't been found any counter example yet.
I think 'Is time an illusion' is akin to asking 'define love'. I know it is corny.
Yeah, probably, just like all human sensory input.