What is the role of life in the universe?

The fact that humans mass produce complex technological devices has absolutely no effect on the overall entropy of the universe at all. Our high-tech products, and our resulting thermodynamic waste is extremely local to planet earth. When our sun goes nova anything that humans have done will be completely erased for all intents and purposes. There simply won't be any net effect to the entropy of the universe as a whole because of our activities.

The idea that somehow we exist because the information content of the universe must be conserved is simply absurd. The evolution of life on earth has extremely local thermodynamic effects that cancel each other out. "Information" could have just as easily been conserved without any need at all for any biological activity.

I don't see where the concept of entropy even comes into play as an explanation for 'why' life might have evolved. We can, however, see why the evolution of life does not violate the thermodynamic laws of entropy. But that doesn't mean that life was somehow required to maintain the entropy of the universe.

That idea simply doesn't hold water.

What is the probability that a universe exists? The only alternative to something (the universe) is NOTHING. In other words, there is no alternative. So the probability of the universe existing is 100%. Right?

Is the complex structure of life an increase of entropy or a reduction of entropy?

Two questions:

What is the probability that a universe exists? The only alternative to something (the universe) is NOTHING. In other words, there is no alternative. So the probability of the universe existing is 100%. Right?

Is the complex structure of life an increase of entropy or a reduction of entropy?

This would be like saying that since I don't play the lottery I can't lose, therefore I must win if I don't play!

What is the probability that a universe exists? The only alternative to something (the universe) is NOTHING. In other words, there is no alternative. So the probability of the universe existing is 100%. Right?

This would be like saying that since I don't play the lottery I can't lose, therefore I must win if I don't play!

According to your post above, the existance of something with a 100% probablility of existance holds NO information. Must we therefore assume that NO information is encoded in the existance of our universe? Do you somehow need to total up the information contained in our universe and arrive at a grand total of NO infomation? Just wondering where this might go...

This passage is located in Susskind's paper: "I make a number of comments about Smolin's theory of Cosmic Natural Selection."

[quote from paragraph 8 of Susskind 29 July paper]

From the final (side by side) statements:

[quote about Overbye, Gerald 't Hooft, etc etc. information that goes in hole cant be lost]

I find this statement to be a bit tough to take. Indeed, "nothing can be lost from the outside world"? If a black hole strips the matter from an orbiting star, and that matter ends up on the opposite side of the BH's event horizon, then matter (and the information that it represents) has disappeared from our universe. In contrast, Hawking radiation - promotion of virtual particles to real status just outside the event horizon, results in a net gain of information in our universe, if we regard virtual pairs as quantum probabilities and real particles as information-bearing entities. Susskind is a smart man, and he drags 't Hooft (a Nobel laureate) in as ballast for his ideas on this point, but I sense a disconnect in his definition of "information". Perhaps it arises from some fundamental differences in the way information is handled in String and QFT as opposed to GR.

That's how I read it.

Let's see. If the entropy of the universe as a whole always increases, then where does that leave the uncertainty of its continuted existence? Does the uncertainty increase or decrease? Is it possible that the universe may one day pop out of existence?

The discussion about black holes "losing information" concerns processes in which a black hole forms and then evaporates. Hawking had conjectured in 1974 that information about the initial state of the universe is lost when this happens. Susskind and others have long argued that this cannot be true, otherwise the basic laws of quantum physics would break down.

As Hawking initially formulated the problem, the black hole would evaporate completely, leaving a universe identical to the initial one, but with less information. This could indeed be a problem, but this is not the situation now under discussion. The present discussion is about cases in which a black hole singularity has bounced, leading to the creation of a new region of spacetime to the future of where the black hole singularity would have been. In the future there are two big regions of space, the initial one and the new one. If this occurs then some of the information that went into the black hole could end up in the new region of space. It would be "lost" from the point of view of an observer in the original universe, but not "destroyed", for it resides in the new universe or in correlations between measurements in the two universes.

The first point to make is that if this happens it does not contradict the laws of quantum mechanics. Nothing we know about quantum theory forbids a situation in which individual observers do not have access to complete information about the quantum state. Much of quantum information theory and quantum cryptography is about such situations. Generalizations of quantum theory that apply to such situations have been developed and basic properties such as conservation of energy and probability are maintained. Using methods related to those developed in quantum information theory, Markopoulou and collaborators have shown how to formulate quantum cosmology so that it is sensible even if the causal structure is non-trivial so that no observer can have access to all the information necessary to reconstruct the quantum state [c]. Information is never lost — but it is not always accessible to every observer.

It would seem that given your model of information, the universe cannot ever cease to exist. It is 100% guaranteed to exist (with an information value of exactly zero) and unless the "information value" of the universe somehow increases, the likelihood of its demise has to be nil. This implies a static infinite universe. I certainly don't have any trouble with such a cosmology, but this model of information has some severe implications for the standard big bang model!

This would be like saying that since I don't play the lottery I can't lose, therefore I must win if I don't play!

No, it's more like: I can guarantee a winner as long as someone plays the game.

I dont understand how there is a case against "black hole universe" idea based on black hole merger.

Recent analysis (like by Modesto, Hosain, ...) suggests that spacetime continues at the former-singularity and undergoes a bounce----that is, it re-expands. Conditions for inflation are present generically (Date, Hussain).

We dont know that the Loop gravity picture is true (of what goes on at center of black hole, or at big bang) or if the bounce is real. But this is the most detailed model we have of how space behaves at these events.


Indeed black holes do sometimes merge, and their inner regions (which used to be considered singularities, before quantization) merge.
If they merge then they merge, regardless. The consequences might well be awful to inhabitants if there were any, totally screwing up the physics of both universes, but that's the breaks. I hope it never happens to our universe.

I can only speculate as to what a merger between two black hole universes might be like. that seems like a good problem for theorists to work on AFTER they get a workable quantum gravity (theory of spacetime) and then build something like the Standard Model into that new framework.
the fundamental physical constants must be intrinsic to however space is represented. I dont see how two universes with different fundamental constants could ever blend, but if they have to blend then it is up to the possessors of a unified theory (a general relativistic quantum physics) to predict the outcome.

I was hearing at the BBC this weekend an interview with James Lovelock, the crator of the Gaia hypothesis, I wonder if some other PF member heard this interview
If you don't know what's about (improbable), its the fact of treating the Earth as a living system able of autoregulation. Wikipedia gives the definition of Gaia according to Lovelock:
"a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet."
http://en.wikipedia.org/wiki/Gaia_theory
I will like to hear opinions of PF members about this, and about the possibility of other high scale structures having life as one of their characteristics

I find interesting that Wikipedia says that there's a distinction between strong Gaia theories and weak Gaia theories

Well, in the case of the lottery even that conclusion would be incorrect. There are often times when no one wins even though thousands of people may have played.

I just don't get your original premise that it would be impossible for the universe not to exist. Yet you seem to have absolutely no problem accepting that idea that information does not exist. (i.e. you claim that the total information of the universe must be zero)

Why would it be impossible for the universe not to exist? Just because you personally view the idea of NOTHING as an impossibility?

I personally find it much more impossible that anything exists at all. Yet it obviously does. The universe is impossibe yet it exists, and that's the mystery. A mystery that I dare say no human will ever know the anwser to. At least not via the use of logical reasoning, because whatever the answer is, it must necessarily be illogical.

I don't think his coacervates are still considered part of the early history of life. Rather than trying to mimic cell walls, reseachers are now thinking of two-base RNA's and self-catilyzing molecules.