“Anthropic coincidences,” expounded upon by Victor Stenger, cannot be a near-deductive argument for theism, because it can always be objected that man is nothing special. Humans, an atheist will argue, are no more interesting, or uninteresting, than sand or bugs. “We” lucked out in the universe-selecting lottery, but so what?
In other words, the near-deductive argument requires a suppressed premise, such as “We were meant to be.” Again, the atheist will request proof of that. If it is replied that we are meant to be because “God loves us,” then this assertion obviously entails “God exists” which presupposes precisely what we are trying to prove.
The fine-tuning argument can be rescued by rephrasing it in Bayesian, and therefore much more inductive, terms.
Let T = theism, FT = the proposition “the universe is fine-tuned for intelligent life.” Then
P(T | FT) = P(T) * [P(FT | T) / P(FT)].
Now P(FT | T) = 1. Remember that theism in its most developed Christian form does insist that humans (together with angels) are the crown jewels of creation. They were always meant to be. Unlike angels, humans have material bodies and physical needs. Hence the universe God created to be a home for man must needs be fine-tuned.
An anthropic argument for the existence of God will then claim that P(FT) is extremely low, and therefore FT confirms T. This is the stage where Stenger comes in with an attempted refutation of this opinion. He proposes 3 objections to it.
1. Stenger attacks “the wholly unwarranted assumption that only one type of life is possible — the particular form of carbon-based life we have here on earth.” (134)
In fact, he speculates, “life might be likely with many different configurations of laws and constants of physics.” (135)
Even stronger, “perhaps life of some sort would have happened whatever form the universe took.” (141)
Well, perhaps. But “perhaps X” implies that X is possible not that it is probable. The fine-tuning argument’s main assumption is precisely the extremely narrow ranges of permitted values which Stenger himself dutifully lists in the first part of the paper.
To put some meat on this objection, Stenger writes that he “analyzed 100 universes in which the values of the four parameters were generated randomly,” etc. “Over half the universes have stars that live at least a billion years. Long life is not the only requirement for life, but it certainly is not an unusual property of universes.” (144) This is an admirable effort but still rather inconclusive, all things considered.
Nevertheless, I agree that we don’t actually know the relevant probabilities of FT in any detail, and this purely logical attack must be judged somewhat successful.
2. There exist in fact numerous but a finite number of actual universes. “André Linde proposed that a background spacetime ‘foam’ empty of matter and radiation will experience local quantum fluctuations in curvature, forming many bubbles of false vacuum that individually inflate into mini-universes with random characteristics. In this view, our universe is one of those expanding bubbles…” (145)
Stenger suggests that the number of universes thereby spawned may be infinite, but that’s a mistake. Since we’re dealing with an actual physical process, this number must be finite, as infinities — mathematical abstractions — are not permitted in physics as far as the ontology of its models is concerned. There can be no actual infinite of real objects.
Moreover, it seems to me that within the universe as it was during its earliest Planck epoch — a black hole of Planck length filling all the tiny space of the universe — only one fluctuation could occur, and it would be both necessary and sufficient to cause the separation of gravity from the superforce, then the separation of positive energy from the negative gravitational energy, and finally expansion and inflation.
Stenger mentions another speculative theory in which “each universe is the residue of an exploding black hole that was previously formed in another universe.” (145) There is “natural selection” as collapsing black holes turn into random universes, such that “by chance some small fraction of universes will have parameters optimized for greater black hole production. These will quickly predominate…” (146) This differs from Darwinism pointedly in that the universes do not interact with one another, and unfit universes do not get eaten or starved by the fit ones. The problem with this idea, of course, is that this process selects for black hole production efficiency and not for intelligent life.
Lastly, if the number of possible worlds is infinite (and there are infinities of ideal objects), then these hypotheses solve nothing: the probability of any finite number n of worlds being randomly spawned is exactly n / ∞ = 0, which means simply that it is impossible fairly to consider for random selection of one member all members of an infinite set. No mechanical random world generator could function under such conditions.
3. There is an infinite number of actual universes: “Tegmark has recently proposed what he calls ‘the ultimate ensemble theory’ in which all universes that mathematically exist also physically exist.” (146)
Again, there can be no such thing; I have suggested that this fact serves as a “sanity test“: those who reject it are not playing with a full deck.
However, if, per impossibile, there could be an infinitude of reals, then I agree that the fine-tuning argument would in that case be undone.
Finally, we have the Stenger’s hypothesis of how natural law was given. He splits this process into two parts:
(1) the breaking of the Planck-epoch primordial perfect symmetries which is itself law-bound; and
(2) random “spontaneous” crystallization or freezing of law as the universe “cooled.”
As regards (2), it uses a bad analogy: “cooling” can freeze matter, not the natural law according to which matter freezes. Further, the random law generator again could work only if the number of possibilities for natural laws were finite, but I think it is infinite.
The bigger problem, however, is with (1), since it postulates a meta-law governing the cosmic becoming. I don’t see how this helps Stenger. Who laid down the alleged meta-law that the symmetries shall be broken?