Various constants of physics are fine-tuned for permitting life.
This page analyzes five examples:
Various initial conditions of physics are fine-tuned for permitting life:
This article analyzes five examples:
Various laws of physics are fine-tuned for permitting life:
A forthcoming page will analyze these five examples:
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
• Douglas Adams (on “puddle thinking”): “This is rather as if you imagine a puddle waking up one morning and thinking, ‘This is an interesting world I find myself in--an interesting hole I find myself in--fits me rather neatly, doesn’t it? In fact it fits me staggeringly well, must have been made to have me in it!’ This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it’s still frantically hanging on to the notion that everything’s going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise.” [Speech at Digital Biota, Cambridge (1998).]
• Victor Stenger: “life as we know it would not exist if any one of several of the constants of physics were just slightly different, [we] cannot prove that some other form of life is feasible with a different set of constants. Anyone who insists that our form of life is the only one conceivable is making a claim based on no evidence and no theory.” [Has Science Found God? (Prometheus, 2003), 156.]
• Sean Carroll: “As skeptical as I am about the ability of physicists to accurately predict gross features of a universe in which the laws of nature are different, I am all the more skeptical of the ability or biologists (or anyone else) to describe the conditions under which intelligence may or may not arise. (Cellular automata, the simple discrete systems popularized by Wolfram and others (Stephen Wolfram, A New Kind of Science (Champaign, IL: Wolfram Media, 2002)., provide an excellent example of how extreme complexity can arise out of fundamentally very simple behaviors.)" [“Why (Almost All) Cosmologists are Atheists” (2003) online at infidels.org ]
• Michael Ikeda and Bill Jefferys: “Indeed, virtually nothing is known about the possibility of life in universes that are very different from ours. It could well be that most universes could support life, even if it is of a type that is completely unfamiliar to us. To assert that only universes very like our own could support life goes well beyond anything that we know today.” [“The Anthropic Principle Does not Support Supernaturalism” (2004) online at talkreason.org]
• 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 his crucifixion. Far from explaining away the evidence, this would obviously just kick 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
Consider two arguments:
This is relevant because if 99% of the Universe is hostile to life (unaided by technology), then the Universe is not very fine-tuned for life.
But so what if it is 99% hostile?…
[Brackets] mean “Forthcoming”
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 then all instances of fine-tuning are equally improbable, be they very fine-tuned or hardly fine-tuned at all.
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 constant 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?