Sorry, but your ant analogy doesn’t seem to be very good for fine tuning.
Fine tuning has nothing to do with how rare our universe is. It has to do with how sensitive habitability is to small changes in the constants. If there were 10^1000 universes, all of them just like ours, so that our universe was the very opposite of rare, that would just mean that all 10^1000 utterly common-place universes were fine-tuned.
Yes we do. We know that any kind of life needs big molecules to store information. You can’t make big molecules from Hydrogen and Helium. You need heavier elements. The only way to make them is inside stars. So you need a universe that can make stars. The ability of our universe to make stars is seen by some to be highly sensitive to the constants and the initial conditions of the big-bang.
Statements along the line of “we don’t really have any idea what can or can’t live anywhere” sound like nobly avoiding carbon chauvinism-- but in reality they are not scientific (in my opinion.)
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How do you know what constitutes a “small” change to a particular constant? Surely this requires one to have some idea of the probability distribution underlying a particular constant? A “Small” change is a change that occurs with a high probability?
No it doesn’t. While it is somewhat subjective, most people who deal with numbers would tend to agree that, say, a 1% change in the strength of the electromagnetic force is a “small” deviation. That is independent of some unknowable probability distribution for the values of the E&M coupling constant (alpha).
Defining small in that way is completely arbitrary. How do you know that when a new Universe arises, that the strength of the electromagnetic force can even vary by 1%. Perhaps it can only vary between -0.5% and +0.5% of what it is in our Universe.
I thought that the main thrust of the fine tuning argument is that it is highly unlikely that a life-producing set of physical constants could have arrived at by pure chance?
I don’t see how such a statement can be justified. To calculate the probability of set of life-producing physical constants occurring in a new Universe, one needs to know the probability distribution of the constants and the range of life-producing constants, both of which are unknown.
No. Such as statement cannot be substantiated since we do not know anything about the likelihood of the constants.The fine-tuning argument is “merely” this: the habitability of our universe appears to be very sensitive to small changes in the constants. Period. It says absolutely nothing about whether the values of the constants are highly unlikely or inevitable. Such arguments are always added in after the fact–typically when someone has an agenda in mind.
Okay. How does one tie the Fine Tuning Argument to “It is likely that the Universe is designed”
At the moment, through philosophy/apologetics (which is just fine), not through science.
Thanks for the info. Just out of interest, do you find any of the fine tuning arguments for gods existence convincing?
No, not as proofs for God. (I don’t find any proof of God convincing.) However, as a believer I find the fine-tuning puzzle to be comforting and faith-strengthening.
Different people use different versions of fine tuning. You are correct that fine tuning can mean exactly what you say, the sensitivity of habitability to physical constants and starting conditions, but others use fine tuning to refer to the possible rarity of our universe.
That is a rather narrow view, IMHO. Are there other possible configurations of constants and particles that would produce packets of matter that aren’t hydrogen, helium or larger elements but are still capable of producing life? I see no reason to limit the possibility of life to just the very specific elements that we see in our universe.
Not that it is the ultimate authority (even though it is when I agree with it!) Wikipedia’s definition of a fine tuned universe is:
The fine-tuned Universe is the proposition that the conditions that allow life in the Universe can occur only when certain universal dimensionless physical constants lie within a very narrow range of values, so that if any of several fundamental constants were only slightly different, the Universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is understood.
Notice it makes no comment regarding the probability of the constants, or how rare our universe is. It simply states as I did, though with more words, that fine-tuning = sensitivity.
For comparison:
Maybe it is arbitrary, in some sense, but it is more or less by scientific consensus. That is, a majority of scientists (well, at least physicists, cosmologists, astronomers, etc.) of all philosophical and religious stripes agree that if changing a constant by 1% or 2% causes the universe to be uninhabitable, then there is an interesting, non-trivial fine-tuning problem/puzzle. I would say when it gets up to about 10% for a given constant you start to get disagreement as to whether that is worthy of “fine-tuning.”
That’s irrelevant. If the habitability of the universe is fine-tuned in regard to alpha, then it is fine tuned regardless of the unknowable range of possible values of alpha. Or even if there is no range of possible values, and alpha has no “choice” but to be what it is.
No. that’s the main misrepresentation of the fine tuning argument. The fine-tuning argument says nothing, absolutely nothing, about how probable or improbable are the values of the constants. Here is wikipedia’s definition:
The fine-tuned Universe is the proposition that the conditions that allow life in the Universe can occur only when certain universal dimensionless physical constants lie within a very narrow range of values, so that if any of several fundamental constants were only slightly different, the Universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is understood.
notice that is says absolutely nothing about chance or probability.
Which is why I am NOT trying to justify the statement you are referring to, a straw-man that adds to the proper definition of fine-tuning weird things like “unlikely” or “by pure chance”. I agree with you. Such things are indeed unknowable. But that doesn’t refute fine-tuning, it refutes a misrepresentation of fine-tuning.
That is not inconsistent with what I said. The money sentence is indeed true:
Fine tuning tells us that, if the laws of physics in any universe were chosen randomly, then it would be extremely rare that a universe could support life. (Emphasis added.)
But that is a corollary to fine-tuning = sensitivity. In other words, if alpha has to be within 1% of its given value, we can say:
Theorem: The universe is fine-tuned in regard to the electromagnetic constant. (And the proof would be showing that if you changed it by 1% everything would go to hell quickly.)
Corollary: Given the fine-tuning of alpha, if alpha is selected randomly (which is not a premise of fine tuning) then we would expect most universes to be sterile, and habitable universes to be rare.
Fine tuning only says something about rarity if you add the proposition that the constants are chosen randomly.
From what I read in the opening post, this is the proposition that is being addressed.
I fully agree that you are describing fine tuning the same way that most astrophysicists describe it.
For me fine tuning strongly i8ndicates that the universe is rationally structured, rather than randomly produced. If there were any tangible evidence for the multiverse, then it would have to be seriously considered as an answer to this question, but there is not. Therefore it seems that God is the most reasonable answer, which does not means that everyone has to agree with it.
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