The Universe Is Not Ergodic | Sean Carroll

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1. do you think that Sean Carrol is one of the top thousand smartest people in the world? or where does he fit into the hierarchy of smartest/best physicsists?
2. As a laymen I can only parse bits and pieces of this, but I enjoyed it nonetheless
3. I love how assumption is pointed out here. something that I wondered when working on my own ideas and if they could be correct, or as correct as current ideas, where both ideas could be wrong, but only one can be right, but because we cant measure all the 'data' there is no way to tell (so we assume)
   
   added:
   As I heard more around 1h mark, sent shivers down my spine, to hear some ideas that gelled with mine :)
4. This lecture is badass. ..lovin' it
5. Carroll destroys the Copernican principle of mediocrity
6. Around 42:00 some good old Measure Theory is required to make sense of Bayes theorem with an infinite sample space
7. the assumption that a universe can exist eternally produces the problem with Poincare recurrence. then why should you suppose that a universe must be eternal? a finite time existing universe hasn't problems of this kind. then why this simple assumption wasn't taken into consideration?
8. I object to all these other characters constantly interjecting. I didn't come here to hear them but Dr Carroll. They should hire their own hall.
9. Just wondering what if sub atomic particle types went on and on to infinity so one could never fully reach a 'final' sub atomic particle which is the base of all particles ? maybe that's a fail safe for a God to prevent lifeforms from truly understanding the nature of the universe(s).
10. This Fermi Pasta is a little too al dente.
11. "Not only does God shoot dice, he rolls an infinite number of them and chooses only those which come up 7 or 11." :)
12. /offtopic
    The 100 door Monty Hall problem is easier.
    There are 100 doors you choose 1, Monty rules out 98 with straw. Do you switch?
    Repeatedly lower the number of doors by 1.
    ...until...
    Classic Monty Hall
    
    
    The probability of the first door chosen is 1/n and that never changes. The 1-1/n probability becomes "concentrated" in the remaining door.
    
    
    observing 1 coin flip of a continuously flipping coin the string is ...1...
    observing 2 coin flips the string is ...11...
    3__ ..111...
    
    
    Given data(3) and t1 that says all will always be 1 (the coin has two sides marked 1), and t2 says coin flips are random (ruling out landing on edge). What are the odds of observing 111 on a fair coin? What about 100 1's in a row? It could still happen, right? In the world where it happens it is simply a datum if taken alone.
    Cosmologists have one observation. We have all 1's for some things. What is the probability that the 1's will continue on T1 vs T2. Bayes' Theorem embodies the axiom of experience: in the future the future will be like the past because in the past the then-future has been like the then-past. When there is just one data set -- one observable universe -- there is no past to plug in to BT.
    
    
    In our one-off we see "big bang conditions." Suppose the size of the universe followed a supremely simple exponential curve k^t. At t=0, the size would be 1 (big bang conditions).
13. Isnt Sean Carroll contradicting himself by saying "I think we are very very far from thermal equilibrium" t=1:05:15 ? It seems that he made the same mistake that he is teaching us not to make with this video. It may seem that what we observe is far from equilibrium but that is no more different than the case with Mona Lisa being formed by chance
14. The Universe is not, ergo dick.
15. Why are we considering such an unfounded, unprovable claim if science is supposedly all about evidence? Does it not apply to The Great Multiverse?
    
    This isn't science, it's pop physics that has been wildly extrapolated onto a system that we simply cannot test these theories on. How about we think about the real world before we start trying to prove or disprove God?
16. Brad, things are a little slow over at my channel...would you mind posting one of your "thoughts" to kick start some good-old-fashioned lunatic bashing on my page.
17. +Ben Carbery Sean is still at Caltech. His latest book is:
    
    "The Particle at the End of the Universe: How the Hunt for the Higgs Boson Leads Us to the Edge of a New World"
    
    But I suspect that he is still heavily involved in time and its relationship with the 2nd Law of Thermodynamics.
18. Let's see if I got this right.  Assuming where we are is a low point of entropy tough we can both explain the relative order we percieve, and why we feel secure in making our various physical claims. Because this low entropy trough is fairly lengthy by human time, so as long as we remain in this trough, claims and predictions limited to this trough can be fairly accurate.  And from our examination of this trough we mistakenly assume, looking outward (and perhaps inward) to the great unknown that all out there in the cosmos is high entropy and getting higher.  This solves the problem of increasing order, at least here on earth, being true, contrary to general entropy in which everything is dead.  But from this poor vantage point we can't even be sure if all out there is increasing or decreasing in entropy. Then the "eternal return of the same" is avoided by positing a fixed number of particles in an ever expanding space, so that recurrence need not happen. 
    
    One problem I see is that all the ideas of probability used in this presentation may only hold true for our little vantage point, as they are birthed in the first place from study of this vantage point.   Another problem I see is that there isn't really a good way to be sure if this vantage point is so poorly situated - it might be a fantastic vantage point for all we know.  
    
    Fantastic, but perhaps not perfect.  If not perfect, then it might be safe to assume that some riddles and paradoxes will persist till the end of human existence.  I'm not saying don't try to figure it out, but we might want to consider the implications of actually not being able to figure it all out.  
    
    Another problem:  Prof Carroll is taking the currently fashionable humility stance, as opposed to the hubristic claim that we can figure it all out, while then going on to say that we can figure it all out.  
    
    If I had advanced degrees in physics I'd be working on turning lead into gold.  I love gold.  Physics and QM especially have tilted from optimism to pessimism in the 20th century.  It's all about what we can't do - it would take too much energy to turn lead into gold, and thus not worth it.   I suggest trying to trick the lead into becoming gold.  How great would it be if a change could be applied to just one atom in a brick of lead, which then led to a chain reaction turning the entire brick into gold!!  And if heat was given off in the process, then use it to make electricity.  And if heat is lost in the process, then every air conditioner and refridgerator/freezer would be a money maker!