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Author Topic: How do we know cosmological fine tuning is "fine tuning" at all?  (Read 2601 times)

Offline norcalclimber

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I keep hearing the term "fine tuning" in reference to the physical laws of the universe.  Supposedly the physical laws are considered to be "fine tuned" because everything works within precise parameters and without such precise parameters, the universe would not function.  I then hear creationists argue "god" must have done it, and others argue that there must be multiple universes and most of these don't work but ours does and so we are allowed to exist. 

The problem I have though, is that in order to consider the physical laws fine tuned, we have to assume there are other possible ways for the physical laws to exist, or work(even if it causes matter to be impossible).  It seems to me, that reality is simply the observation from an individual particle of the interaction between itself and space and all other relative particles.  It seems to me that all forces are simply the response of space to the interaction between a specific particle and space.  Since a particle in this case can be defined as any individual particle, or any collection of particles, then a force like the gravity produced by our sun, is simply the collective sum of the individual forces of all relative particles, or the individual effect of the sun as a particle.

If every physical law simply describes the action of a specific particle and the equal and opposite reaction of space or another particle, doesn't this bring about an inherent balance, which could appear to be "fine tuning" when in reality it is simply the only possible way for anything to exist in the first place?  In other words, wouldn't a basic law that every action must have an equal and opposite reaction make it so that all physical laws would appear "fine tuned" from our perspective.  Isn't even the term "fine tuning" highly subjective anyway?  Since the most basic particles are much smaller than us, many things would appear "fine tuned" from our relative place of observation, but isn't that completely subjective?

 Perhaps I am misunderstanding a lot, please correct me if that is the case.
« Last Edit: 18/02/2010 18:20:24 by norcalclimber »


 

Offline PhysBang

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You have hit the nail squarely on the head. Fine tuning arguments make assumptions about the probabilities of certain physical laws turning out the way that they have, but we do not have a way to assign these probabilities. There may be, as you say, only one way for the physical laws to be.
 

Offline Madidus_Scientia

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http://arxiv.org/PS_cache/arxiv/pdf/0807/0807.3697v1.pdf

This paper suggests that even in hypothetical universes with cosmological constants varying by orders of magnitude, stars are capable of forming in 25% of them.
 

Offline norcalclimber

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Thanks for the responses  :)

The question I have for anyone when thinking about hypothetical universes is this: It seems to me that everything is connected and influenced in some way, no matter how small, by everything else.  So how do we know that if we change some force or law in some small way, that it wouldn't create a cascade of changes in all other forces which would result in a universe which works just fine, with the same basic structures, matter etc. as ours, causing it to be basically indistinguishable from ours?
 

Offline PhysBang

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I think that when physicists imagine hypothetical changes to various laws, they imagine that the change is relative to the other laws as we currently understand them. This makes the assumption that there isn't some underlying relationship between the way the laws work as you suggest, but since nobody has established that there is such a relationship, it doesn't seem to tug speculation in one way or the other.
 

Offline Soul Surfer

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I think that this fine tuning  is a topic that will eventually get its due attention from the theorists.

One must not forget the effect of quantum mechanical uncertainty in the big bang model

The basic big bang model is based on the physical laws as we see the m now in a cold universe and describes the various symmetries breaking "randomly" and says that what we see fits very well with the model but that this random symmetry breaking looks improbable.

They do not realise that lower energy processes can affect the results of experiments and that it is highly probable that the symmetry breaking is not random but that all universes expanding from a big bang select the maximum possible complexity and recycling that is available to them.

Let me explain.  It is a bit like one of those magnetic executive toys where you have a pendulum and some magnets arranged in a pattern.  When the pendulum is swinging widely it largely ignores the magnets but as the oscillations decay the magnets have more and more effect and the pendulum swings wildly in complex patterns.  now let us consider the quark soup cooling down if some conditions occur where quarks can combine to form nucleons and these live longer and are more isolated than the quarks the formation of nucleons will be preferred and similar as electrons join with  nuclei to form atoms  so like crystallisation a complex pattern emerges from a random solution because it is more stable and long lived and therefore preferred over transient random interactions.
 

Offline norcalclimber

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Very interesting thoughts Soul Surfer, and it makes a lot of sense.  Quantum mechanics should have a huge impact on the physical laws, because all we see is simply a collection of quantum particles.

There is also one thing which all particles large and small in the entire universe have in common...space.  If space has enough substance to be curved by gravity, then it makes sense that it would interact with all particles, quantum and macro.  Any observation needs a frame of reference, and interaction with space is the most basic frame of reference possible, IMHO.
 

Offline norcalclimber

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It has been pointed out to me that my subject of my posts should be formed in proper questions, so I have edited this post to reflect that.
 

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