Time's Illusion

March 5, 2009 10:54 PM

The thermal time hypothesis.

In which Carlo Rovelli and Alain Connes suggest that time does not "exist" as a fundamental feature of the universe, but is an emergent property based on the collapse of the probability of independent events into the probability of a series of events.

Discuss amongst yourselves.

posted by CheeseDigestsAll (36 comments total)

If time doesn't exist, what makes my clock go?
posted by aubilenon at 11:10 PM on March 5

If time doesn't exist, what makes my clock go?

The article doesn't say. Yay bad science writing!
posted by delmoi at 11:13 PM on March 5

Re-written as an Onion Headline:

Scientists cut budget, time, from quantum mechanics research.
posted by fontophilic at 11:16 PM on March 5

As much as I dislike Scott A. Aaronson, this article actually does a pretty good job of explaining how time is treated in relativity, and how it's different from space, unlike the newscientist article which doesn't really get into any math.
posted by delmoi at 11:20 PM on March 5 [2 favorites]

If time doesn't exist, what makes my clock go?

The battery, silly.
posted by stavrosthewonderchicken at 11:30 PM on March 5 [2 favorites]

Well, duh.
posted by TwelveTwo at 11:31 PM on March 5

The bottled time hypothesis.
posted by homunculus at 11:47 PM on March 5

lunchtime doubly so
posted by oonh at 11:48 PM on March 5 [5 favorites]

So here I am reading about how time is just an illusion, when I ought to be typing frantically to meet a deadline on a project. Oh, the irony. I suppose emailing the client this article won't buy me a few more hours, however.

Great post - reminds me that NS still turns out really good science journalism now and again.
posted by dowcrag at 12:27 AM on March 6

in that science writing is often an exercise in flattering the audience on their pretence of understanding, then yea, "bad science writing!" but i, for one, appreciate the attempt :P

and in that vein of pretending to understand, i'll attempt a comment...

nothing is real

The probabilities of the possible outcomes will depend on the order in which we perform the measurements.

first off, expressing my ignorance, is this a 'noncommutative geometry'? also i wonder if feynman's admonition is applicable: "The only difference between a probabilistic classical world and the equations of the quantum world is that somehow or other it appears as if the probabilities would have to go negative," cf. exotic probabilities

These are forms of probability theory that share many of the usual axioms of probability theory but in which the probabilities themselves lie in a set other than the non-negative reals eg. the complex numbers, the quaternions, or even the p-adics. The primary motivation is that classical mechanics plus complex probabilities looks a lot like quantum mechanics, and so if you believe in complex probabilities you no longer have to worry about things like wavefunction collapse.

speaking of which, mix in a little zurek and add a dash of markopoulou-kalamara and i'll collapse your wavefunction on my measuring device :P

...and where do the probabilities arise from anyway? like time/temperature, is it merely 'the effect of our ignorance'?

the dynamics of the universe can be described as a network of correlations, rather than as an evolution in time

the article mentions barbour; i like this quote by him:

"Obviously, as macroscopic human beings, we don't change much from second to second. And there's no question that we're the same people. I mean only an extreme madman would deny that," he says reassuringly. "To that extent, it's true that we do move from one Now to another. But in what sense can you say we're moving? The way I see it, not exactly the same information content, but nearly the same information content, is present in many different Nows."

reminded me of clockless computing or the universe as a spreadsheet or possibility space (with some states more accessible than others)

anyways, thanks for the article!
posted by kliuless at 1:24 AM on March 6 [1 favorite]

Nice article. I enjoyed the subtle irony that the title of the page is:


"Is time an illusion? - 19 January 2008"
posted by forrestal at 2:23 AM on March 6

Yeah, the whole idea of time as a continuous linear extension of experience, akin to the three extensional dimensions of space, has always been problematic for me and my immediate family.

It's not so much a problem for me, because I'll believe any weird thing, but it's been a problem for my wife. When I show up at 4 AM and she happens to be awake she always asks where I've been for the last few hours. And I try to explain that Time and Space are relative - that 4 AM here is actually 9 PM elsewhere, and that the basic Laws of Physics preclude an immutable reference point, so I may have returned home several hours ago, relativistically speaking.

My wife has become increasingly annoyed with my efforts to explain my behavior in terms of relativistic temporality. This I ascribe to her lack of knowledge of basic physical principles, which allow husbands to stay out later than wives.
posted by twoleftfeet at 3:10 AM on March 6 [4 favorites]

Oh, and Alain Connes is a truly great mathematician.
posted by twoleftfeet at 3:31 AM on March 6

Previously.
posted by mek at 3:51 AM on March 6

An emergent property of a demand that others "discuss" your post is being thought a twit.
posted by seanmpuckett at 4:29 AM on March 6 [1 favorite]

Great article, and in before Time Cube.
posted by kldickson at 5:23 AM on March 6

EARTH HAS 4 CORNER
SIMULTANEOUS 4-DAY
TIME CUBE
IN ONLY 24 HOUR ROTATION.
posted by kcds at 5:25 AM on March 6

Round these parts, we call the thermometer the "temperature clock." I thought it was cuz we was drunk that first time, but I guess now we was just being accidental scientificalists.
posted by 0x029a at 5:48 AM on March 6

kliuless: Feynmann's comment looks to me like mathematics leading science, rather than science leading math. This is analogous as words leading thought rather than thought leading words. When words lead thought, what we get is Nostradamus's quatrains: we fit meaning to the words instead of words to a meaning. With Feynmann's quote, the math comes first, then try to fit the facts to the math. I think this is bogus just like quatrains and horoscopes.
With sciences, we must get facts first, and then we can use mathematics to compress the information into concepts. Mathematics is not the language of the universe, it is the language of the human mind and it can be used to express incredible fantasy too.
posted by Osmanthus at 5:51 AM on March 6

"The first thing to do is consider time as officially ended...we work on the other side of time."
posted by pziemba at 6:06 AM on March 6 [1 favorite]

a quarter to nine
posted by kitchenrat at 6:13 AM on March 6

For some reason, what I understand of this completely makes sense to me (which probably means I don't understand it right.)

I've always felt that the whole worrisome nature of quantum mechanics and probabilities rested on the fact that single events were being considered. It's sort of like the reverse of the gambler's fallacy. Yes, if I roll a photon, it could end up here or here or here, but if I'm being asked to bet on a particular chain of events, then I have to multiply the probabilities, and then I only get the really likely ones.
posted by CheeseDigestsAll at 6:31 AM on March 6

What I've always found interesting is that, in thermodynamics, you see an arrow to time. Individual events on the subatomic scale are reversible, but somehow we go forward when you get bunches of them together. And then there's that weird bit where only time has a minus sign in the metric (and with all of the squaring of terms, people get all twitchy when they think about imaginary numbers applied to reality).

Are the two related? Does a third thing happen to make these two occur? Is it a happy coincidence? I've often wondered if it would be an interesting avenue to pursue (in a rigorous fashion, of course).
posted by adipocere at 6:59 AM on March 6

"Time is what keeps everything from happening at once. Space is what keeps everything from happening to me." (attributed to John Wheeler).

So, and this may be an askme question, what does the Pauli exclusion principle suggest about time and space? Because it seems to me, from a very casual study of this stuff, that time and space as we know them would emerge while massive particles obey the exclusion principle.

The road-trip and map analogy suggests to me is that time can be avoided in calculations by outsourcing, which doesn't seem that helpful. On the other hand, the gas temperature analogy makes me wonder about computational models of the cosmos which are alluded to. It would be an enormous drain of memory to keep track of the position and momentum of everything at once. It would be better to only require that information only when some interaction specifically requires it. So where does that information go when it's not required? How is it retrieved? Basically, what are the interactions that make reality real?

Obviously I don't know anything about this but I like to read about it and think it's fun to think about. Thanks CheeseDigestsAll and kliuless!
posted by wobh at 7:17 AM on March 6

You see an arrow to time. Yes.
posted by mek at 7:17 AM on March 6

Time flies like an arrow. Fruit flies like a banana.
posted by Foosnark at 7:28 AM on March 6 [2 favorites]

That's an interesting observation about thought leading words vs. words leading thoughts. It covers exactly what's wrong with the word "observation", and perhaps even "collapsing probability". The former implies conscious analysis, rather than blind interaction. The latter...well, the latter discounts the possibility of a quantum PRNG, to a degree that's a little problematic. Not all undecodable processes are random.
posted by effugas at 7:29 AM on March 6

Math has to lead observation in physics to some extent, because for a given set of observations and confidence measure, there are infinitely many rules that fit. Physicists choose the rules that they like mathematically, guided by the observation that so far, physical laws seem to be describable in mathematically compact ways.
posted by grobstein at 8:26 AM on March 6

Man, I fucking HATE pop-sci articles that are written poorly.

This is the second article I've read recently that is so poorly written that instead of clarifying anything it makes it muddier.

Using specific terms such as spin in a way that, AFAIK, isn't homologous to what "spin" actually is in quantum mechanics.

Saying things like "what to one observer appears as time, appears to another observer as a mix of space-time" WTF does that even mean? I know what general relativity is. But that? That's horseshit is what that is. It makes no sense.

Does anyone have any other good popular articles on the topic? IANAP, so math-y stuff isn't good for me. But clearly written articles do massive wonders for my soul.

Ugh.
posted by symbioid at 9:31 AM on March 6 [1 favorite]

New Scientist is always guilty of these sins. It's rare that I know enough about a topic to second-guess them, but muddy writing and scientific imprecision is universal. IMHO they suck.
posted by grobstein at 9:51 AM on March 6

Interesting.
posted by fantabulous timewaster at 9:56 AM on March 6

Anyone seen this week's episode of Lost? Whoa...
posted by ericbop at 10:05 AM on March 6 [1 favorite]

It's still nine-thirty.
posted by rifflesby at 10:23 AM on March 6

Just as long as I don't have to wear my Hammertime pants anymore.
posted by Smedleyman at 4:55 PM on March 6

What. You guys all wore those pants, right? They’re so fresh. Were, I mean.
Shut up. Like these thermal pants are any better. Let’s see Carlo Rovelli do the Running Man without collapsing the wave function.
posted by Smedleyman at 5:01 PM on March 6

Rifflesby, it's definitely after midnight.
posted by mek at 9:20 PM on March 7