debate-points, existence-of-godIn short, one form of the the argument goes:
See also: http://en.wikipedia.org/wiki/Fine-tuned_Universe
What is the most compelling refutation of this argument?
The diameter of the observable universe is approximately 880,000,000,000,000,000,000,000 kilometers long (i.e. the Universe is larger than that). By contrast, the average diameter of our planet is of 12,742 km. It's estimated that there are over 100 billion galaxies.
In other words, the Universe is really, really big and we are but a tiny fraction of it.
Put like that, it sounds absurd that a being powerful enough to control the constants of the Universe would adjust the constants of the Universe just so that there could be life on Earth. Surely, if such a being existed and had the intention to create a universe suitable for life, he would have created a universe more suitable for life than the one we have.
As Neil deGrasse Tyson so eloquently put it, most of the Universe wants to kill us or is unsuitable for life.
In fact, if the Universe is expanding indefinitely, it'll eventually extend to the point where it will be too cold (i.e. under 1 Kelvin) and thus be unsuitable for life. If that's the case, should we conclude that the Universe was fine-tuned to create us and then inevitably kill us?
Then, you have to consider how long it took for us to exist:
If the Universe was really created with intelligent life in mind, our Universe seems like a really ineffective way to do it. It could better "fine-tuned" than it is.
If God created us, He was really, really patient.
Once you digest all that, you have to consider three other things:
In other words, the Universe does not look like it should if it had been fine-tuned for us and, even if it was, it wouldn't mean anything with regards to the existence of god.
And that is without even getting into the possibility of a multiverse.
The fine-tuning argument presumes our universe is the only one, and our set of physical constants is somehow remarkable.
However, many cosmological theories predict there are many, perhaps infinitely many, universes with various fundamental physical constants. If that's so, it's not surprising there would be a universe like ours that happens to support our kind of life. This is generally known as the anthropic principle.
There are a bunch of possible answers to this one, all of which delve into the hypothetical and highly theoretical.
First, this is a “god of the gaps” question. Right off the bat, just because we don’t know the actual answer, that doesn’t necessarily mean that a supernatural (and likely, Judeo-Christian) god is the answer. If someone insists that their god is the answer to the question of the unknown, they are probably not willing to debate it honestly and openly, so keep that in mind before you delve too far into debating this person.
Second, we don’t know how fine-tuned it really needs to be in order to support the physics as we know it. If a given constant we know as being X works for the universe as we know it, we only know that X works. That doesn’t mean that X+1, or 2X or even X^2 wouldn’t work. We just don’t know how great a range for viable values for that constant there really is.
Third, even if we can deduce some kind of narrow range for these variables, how are we to know that this is the only time that some physical properties have been approached, and, when the matter didn’t behave in a manner sustainable to, well, anything, it could have collapsed back upon itself or gotten blown apart (using entirely physical and natural phenomena) until it got it “right.” Think of how biological evolution works: how many species have had to die out, historically, in order to give us the species we know today? Why should any other physical constants in the universe really be any different?
Fine tuning a property of a physical theory, not of nature itself. This is a crucial point which has been implied by other responses, but I think which bears elaboration.
Fine tuning is, loosely speaking, a statement about the fraction of the volume of parameter space of a theory which gives a realistic description of nature. A finely tuned theory only works for a very small region of parameter space, suggesting that the theory itself might be “overly engineered” to make it work. Basically, when trying to come up with a theory, it is easy to jury rig some ideas together that would produce unrealistic behavior, but that this behavior is hidden by fine cancellations or making some effects minuscule by hand (as opposed to a consequence from some principle). It’s basically a way to guess at the likelihood of a theory being accurate, when many theories make equally accurate predictions of nature.
An example might clear things up. There is a problem in particle physics called the “Hierarchy Problem,” where the mass of Higgs Boson would be far too large without lots of fine tuning in the Standard Model. Other theories, such as low energy supersymmetry don’t require this fine tuning, and so are said to “solve the Hierarchy Problem”. This is a major reason why physicists are studying supersymmetry, even though there are no experimental results to date that mandate it.
When people say the Universe is fine tuned for life, they really mean that the Standard Model and General Relativity are fine tuned for life. The fine tuning may disappear or be reduced in a more accurate theory. Perhaps there is even a zero parameter theory, which couldn’t have any fine tuning at all.
In short, the fine tuning argument really says that our best explanations, to date, don’t explain some coincidences. Should we really be surprised if there are some mysterious coincidences in things we don’t understand yet?
In short, the typical counterargument is the anthropic principle. That is, the constants have an acceptable value to support life, precisely because we are there observing them.
Now, let's discuss this a bit in length.
What is an acceptable value range for the constants?
We don't seem to have a clear answer to this, because we don't know what the exact conditions for intelligent life to form are. For example, some finely tuned coincidence allows carbon atoms to form in abundant quantities. Life, as we know it, is based on carbon - so apparently it would look like a 'miraculous' coincidence. Well, yes - as long as carbon is a prerequisite for intelligent life (we don't know that for sure), as long as there is no previously undiscovered physical law that mandates that "coincidence", as long as no other "coincidences" are always formed by changing the constants, etc.
So there's much we don't know and especially we are not really sure that we have a problem at all!
What is the scientific consensus on the (strong) anthropic principle?
Most physicists are not very happy with it, because it doesn't explain anything basically. If a multitude of universes were created, each with its own constants set, then it would be fairly unsurprising that we live in one with a set such as to support intelligent life. However, postulating multiple universes is not really an accepted theory at the moment as obviously experimental proof is necessary, and we have no idea yet on how to find it.
So in other words, use the anthropic principle lightly - certainly more lightly than Dawkins does in The God Delusion. Things are very grey in that area scientifically. It's mostly philosophy for now.
What would the consequences be, if we could prove that the constants are effectively fine-tuned?
First of all, it would not prove anything regarding an intelligent designer of the universe. For example, what would his/her constants look like? The argument is no different from having discovered that we had a big bang - it doesn't imply a creator at all.
What it actually implies, is that there has to be a mechanism by which the constants are tuned to the values they have. In other words, it would become an open problem of physics, just like many others.
I don’t recall if this is Dennett’s or Dawkin’s perspective, but I like it. Imagine you have the time and resources to engage all 7 billion people on the planet in a massive coin-flipping tournament. We can set the rules as “The person who flips heads when the other flips tails is the winner in each round.” We start with 3.5 billion flips, and the winners advance in the brackets to flip again. Sometimes a bracket may have to flip multiple times until a heads/tails mismatch occurs.
Eventually (I’m not doing the math to determine just how many consecutive flips would be required (especially since I introduce the multiple flips per round option) a “winner” will emerge.
“It’s a miracle!! What are the odds that one person could win by flipping correctly that many consecutive times? There must be a plan or purpose!!”
The universe is much like that: every element in it has been engaged in an evolutionary coin-flipping experiment since…. well, a long, long time ago, and we are here living in the result of it. We just ARE the results of a long chain of events. Nothing in the chain implies “tuning” of events.
I believe this is just a re-statement of the anthropic principle.
One counter-point:
In order to say that the observed values of the physical constants is unlikely we need to know
We don’t know either of these things so it’s really impossible to say how unlikely the observed values are.
Copied from asktheatheists.com (bitbutter's answer).
Versions of the fine tuning argument contain hidden premises. Once these are spelled out, its weaknesses are very obvious. In a nutshell the argument says that there are certain values associated with how our universe behaves (the cosmological constants) that, if they had been even slightly different, would not have allowed life to emerge—the conclusion is that the universe was probably 'fine tuned’ so that life would emerge.
The hidden premises are as follows (based on The Fine-Tuning Argument Revisited by Theodore Drange):
P1. The set of cosmological constants we see in our world is just one of a vast number of physically possible sets.
P2. Among the physically possible sets of constants, the set we see in our world is no more likely, a priori, to exist than any other.
P3. It is not the case that there are (or have been) regions of spacetime with different cosmological constants than the ones we see in our world.
C4. From p1,2,3 the existence of the set of cosmological constants in our world is exceedingly unlikely.
P5. Our set of constants is the only physically possible set that would allow the emergence of life as we know it.
P6. The capability of permitting life as we know it to exist, is a very special feature within the set of hypothetically possible worlds.
C7. from p5, and p6, the existence of our set of constants is surprising, remarkable and in need of explanation
Premises 1, 2, 3, and 6 all need to be positively argued for in order to prop up the argument from fine-tuning. So far I haven’t found advocates of this argument who are capable of doing so.
Premise 5 (that life couldn’t have emerged with different cosmological constants) has been contradicted by the work of Fred Adams, among others.
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