Various initial conditions of physics are fine-tuned for permitting life:
• …[initial mass-density of the Universe]
• …[initial distribution of mass-energy]
• …[Big bang “explosion” strength]
• …[strength of density perturbations yielding star formation]
• …[density-ratio of radiation to normal matter]
Various laws of physics are fine-tuned for permitting life:
• …[strong nuclear force]
• …[electromagnetic force]
• …[Bohr’s quantization rule]
• …[Pauli exclusion principle]
The Universe is only fine-tuned for permitting life as we know it.1 (Supposing otherwise is a kind of “carbon chauvinism.”)2
By way of response, however, the Universe has to be fine-tuned in several respects in order to permit any kind of life (and certainly intelligent life). Some tamperings prevent chemistry itself, or leave one with a universe consisting of only the lightest elements (hydrogen and helium).3, 4
• Stephen Hawking: “Of course, there might be other forms of intelligent life,… Nevertheless, it seems clear that there are relatively few ranges of values for the numbers that would allow the development of any form of intelligent life. Most sets of values would give rise to universes that, although they might be very beautiful, would contain no one able to wonder at that beauty.” [A Brief History of Time (Bantam, 1988), 125.]
Graham Oppy (Athest philosophy professor at Monash University): “in a universe in which there is nothing but hydrogen, there plainly won't be life as we know it, and moreover, it seems plausible to suppose that there won't be any other kind of life either.” [Arguing about Gods (Cambridge, 2009) 201.]
Some theory of everything fixes the constants etc. such that there are no free parameters (e.g. M-theory, where it is perhaps naturally impossible for them to be different than what they are).
So what if that was true? That would just push the improbability up to another level, like the proverbial ruck in the carpet. If the values of the constants are necessary for a given law, that raises the question of why a law like that exists. I.e why should the law be such that it can only produce a fine-tuned system, when there are many other possible laws that could exist instead that are not likely to produce a fine-tuned system. To illustrate, imagine some Grand Unified Theory resulted in Jesus uniquely walking on water and resurrecting after crucifixion; far from explaining away the evidence, it merely kicks the problem upstairs to the superlaw itself.
• Bernard Carr and Martin Rees (Astrophysicists, professors): “…even if all apparently anthropic coincidences could be explained [in terms of some grand unified theory], it would still be remarkable that the relationships dictated by physical theory happened also to be those propitious for life” [“The Anthropic Cosmological Principle and the Structure of the Physical World” Nature 278 (1979): 612.].
Over 99% of the Universe’s area is uninhabitable.1
• …virtually all of its locations do not contain breathable air.
• …virtually all of its locations are too hot/cold for us live in.
But so what if its 99% hostile?…
• …our universe is still 100% life-permitting (our physics 100% allows for life).2
• …if this is an evidence against theism, it’s off topic.3
[Brackets] mean “Forthcoming”
The there is an unbounded range of possible values that could be taken for a given constant, then no meaningful probability could be assigned to one landing in the life-permitting range. After all, the probability of landing in the life-permitting range will always be 1 over infinity, i.e. zero or undefined. It presumably can't be undefined, because then the fine-tuning argument from probability goes out the window, and it can't be zero, because that is counterintuitive and and then all instances of fine-tuning are equally improbable, be they very fine-tuned or hardly fine-tuned at all.
But no... • So-called “countable additivity” (i.e. “finite additivty” applied to the infinite) is false; you can't assume epistemic probability for an entire region is the sum of th eindividual probabiliteis of each finite disjoint region.1
The ostensible fine-tuning in the Universe will wash away with new knowledge.1
By way of response, however physicists do not seem to think the fine-tuning will wash away, especially not all of it (any more than we think that all the evidences for an old Earth, or for plate tectonics, will wash away). For example,
• John Leslie (Non-theist philosopher of science, professor at Guelph): “In a book of mine, Universes (1989), I made a long list of such claims about fine-tuning. …What is impressive, I suggest, is not any particular one of the claims about fine-tuning, but the large number of claims that seem plausible, and the consequent implausibility of thinking that every single claim is erroneous.” [“The Meaning of Design” in God and Design Ed. Manson (Routledge, 2003), 56.] (e.g. “clues heaped upon clues can constitute weighty evidence despite doubts about each element in the pile” [Universes (Routledge, 1989), 300.])
If the range of values a contant could take fall along an infinite scale of possibilities, then the rational epistemic prior probability of the Universe being life-permitting (on naturalism) is the same regardless of how restrictive the life-permitting range seems to be. In the end, it is all infinitesimal, which renders recent scientific discoveries pertinent to fine-tuning virtually irrelevant to the fine-tuning argument.
But so what?
• The range is not infinite.1