The fine-tuning argument is an attempt to show that the universe is designed. The basic idea of the argument is simple: the parameters of physics and the initial conditions of the universe are such that if some of them, such as the cosmological constant and the gravitational constant, were slightly different, the universe would not have existed. There might still be a universe, but a short-lived or unstable one that does not allow life chemistry, and hence no life --- the universe is intentionally fine-tuned for life.
Let us assume that the physics used in the argument is all correct. Let us even assume that there is no other explanation of the apparent fine-tuning of the universe than that the fine-tuning is actual and intentional. That is, let us assume that the universe does have a fine-tuner or designer.* Call the designer D. What attributes should we ascribe to D? It is clear that D has to be extremely intelligent and powerful (designing a whole universe is no small task!), but do we have reason to believe that D is omniscient and omnipotent?
Although D does not have to be omniscient to design the universe, D may be omniscient. We have no reason to think one way or the other as far as the fine-tuning argument is concerned. However, if D is intelligent enough to avoid doing things that are unnecessary, we do have reason to believe that D is not omnipotent. Consider the following argument:
(1) D fine-tunes the universe for life.
(2) If D is omnipotent, D does not need to fine-tune the universe for life.
(3) D is intelligent enough to avoid doing unnecessary things.
(4) Therefore, if D fine-tunes the universe for life, D needs to do it that way. [from (3)]
(5) Therefore, D needs to fine-tune the universe for life. [from (1) and (4)]
(6) Therefore, D is not omnipotent. [from (2) and (5)]
Anyone who accepts (1) and (3) has to accept the conclusion that D is not omnipotent if she also accepts (2). People who employ the fine-tuning argument certainly accept (1), and it is safe to assume that they accept (3) as well. Do they accept (2)? They have to accept it if they accept all of the following claims:
- If D is omnipotent, D is capable of creating life that is not carbon-based.
- If D is omnipotent, D is capable of creating life of some form in a universe that is utterly different from ours (with different parameters of physics and initial conditions).
- If D is omnipotent, D is capable of creating life of some form even in a short-lived and unstable universe.
They have no reason not to accept these claims because none of the consequents of the conditionals describes an ability to do something that is logically or metaphysically impossible.** So they have no reason not to accept (2).
If God is omnipotent, then D is not God. This is presumably disappointing news for those who employ the fine-tuning argument.
* The fine-tuning argument does not give us any reason to think that there can only be one designer, but for my purposes here it's not necessary to consider the possibility that there is more than one designer.
** Some philosophers argue that 'omnipotence' is an incoherent concept. Here I assume for the sake of argument that the concept is coherent and that the only things an omnipotent being is incapable of doing are those that are logically or metaphysically impossible.
There is the issue of what context is used to determine the significance of 'slightly' in 'slightly different'.
ReplyDeleteNot really anonymously, Bill Lawson
'Slightly different' in the following sense: If the initial explosion of the big bang had slightly differed in strength by as little as 1 part in 10^60, the universe would have either quickly collapsed back on itself, or expanded too rapidly for stars to form. In either case, life would be impossible.
DeleteWhether 1 part in 10^60 is slight or not, I was thinking of a passage in Sober's Evidence and Evolution, in the first chapter that goes:
DeleteWhere Prob -MT stands for probabilistic modus tollens
"(Prob-MT) Pr(O |H) is very high
notO
Therefore notH
According to probabilistic modus tollens, if the hypothesis H says that O will very probably be true, and O turns out to be false, then H should be rejected. Equivalently, the suggestion is that if H says that some observational outcome (notO) has a very low probability, and that outcome nonetheless occurs, then we should regard H as false. I draw a double line
between premises and conclusion in (Prob-MT) to indicate that the argument form is not supposed to be deductively valid. But maybe it is a sensible form of inference nonetheless.
Friends of (Prob-MT)[probabilistic modus tollens] need to say where the probability cutoff for rejection is located. How low must Pr(O|H) be for O to justify rejecting H? Richard Dawkins (1986: 144–6) addresses this question in the context of discussing how theories of the origin of life should be evaluated. He says that an acceptable theory can say that the origin of life on Earth was somewhat improbable, but it cannot go too far. If there are n planets in the universe that are ‘‘suitable’’ locales for life to originate, then an acceptable theory of the origin of life on Earth must say that that event
had a probability of at least 1/n . Theories that say that terrestrial life was less probable than this should be rejected. Creationists also have set cutoffs. For example, Henry Morris (1980) says that theories that assign to an event a probability less than 1/10^110 should be rejected, and William Dembski (2004) says that a theory that assigns to a ‘‘specified event’’ (a technical term in Dembski’s framework) a probability less than 1/10^150 should be rejected. Morris and Dembski obtain these numbers by attempting to calculate how many times elementary particles could have changed state since the universe began.
Dawkins, Dembski, and Morris have all made the same mistake. It isn’t that they have glommed on to the wrong cutoff. The problem is deeper: There is no such cutoff. Probabilistic modus tollens is an incorrect form of inference (Hacking 1965; Edwards 1972; Royall 1997). Lots of perfectly reasonable hypotheses say that the observations are very improbable. As noted earlier, if H confers a very high probability on each of the observations O1, O2, . . ., O1,000 (but a probability that is short of unity), it will confer a very low probability on their conjunction, if the observations are independent of each other, conditional on H. A probability that is very large but less than one, when multiplied by itself a large number of times, will yield a very small probability. Adopting probabilistic modus tollens would have the effect of eliminating all probabilistic theories from science once they are repeatedly tested."
"(2) If D is omnipotent, D does not need to fine-tune the universe for life."
ReplyDeleteD needs to fine-tune the universe for life in order to show that the universe is designed.
:P
This comment has been removed by the author.
ReplyDelete(3) D is intelligent enough to avoid doing unnecessary things.
ReplyDelete(4) Therefore, if D fine-tunes the universe for life, D needs to do it that way. [from (3)]
(3) does not entail (4), since it could be the case that D does it for fun