In Faith and Philosophy (January 2007), Elliott Sober once again takes up the question of intelligent design (ID) theory, arguing that the minimalist ID (mini-ID) theory–despite what its proponents claim–has theological implications. Here is how Sober describes mini-ID theory:
…mini-ID theory, says only that the irreducibly complex adaptations that organisms possess were made by one or more intelligent designers (Behe 1996, 2005; Dembski 1995, 1998b, p. 15). The identities of these designers are not specified; maybe the vertebrate eye was made by a team of Extra Terrestrials or by a God who lives outside of space and time. The mini-ID theory does not deny that human beings have common ancestors with other species, nor does it insist that the earth is young, nor does it offer an explanation of the origin of the universe. The mini-ID theory differs from some earlier versions of Creationism by virtue of its modesty. (p. 72)
After discussing individual theorists’ personal motivations for holding mini-ID theory, Sober returns to the theory itself, arguing that when taken with a set of independent premises–some of which are independently supported, all of which are held by most mini-ID theorists–mini-ID theory implies the existence of a supernatural mind. Essentially, the premises are these: (i) for any x in nature, if x is an irreducibly complex mind, then x was created by an irreducibly complex mind; (ii) Some irreducibly complex minds are found in nature; (iii) causes precede their effects; (iv) the universe is finitely old. The implicit conclusion seems to be this: Since mini-ID theory, when conjoined with these independently supported premises, implies a supernatural conclusion and since supernatural conclusions cannot be empirically tested, mini-ID theory cannot be a scientific theory.
I have been thinking about how a mini-ID theorist might respond. Now, for the record, I’m agnostic on whether mini-ID theory is true. I just don’t know, and frankly I’m unconcerned with that debate (which, however, is not to say that I believe that its turning out true would be uninteresting! But that aside…). I’m not even really concerned here whether mini-ID turns out to be a scientific theory. My concern is more general: Does a theory’s implying a supernatural (theological) proposition ipso facto make that theory unscientific? I think not, and I’ve been toying around with a modal argument to that end. I thought I would see what FSPB readers think about it.
Let’s get some assumptions and terminology out of the way. First, I shall assume that Sober’s explicit argument is sound; that is, that mini-ID when conjoined with the four independent premises above, entails the existence of a supernatural mind. Second, I shall assume that the mini-ID theorist takes these four premises to be true. Third, I assume that the proposition ‘There exists a supernatural mind’ is a theological proposition (contrary to what others have argued) and thus that ‘God’ and ‘supernatural mind’ refer to the same entity, viz., God. (Therefore, I shall use ‘God’ to refer to the supernatural mind in question.) Finally, I shall assume that the Standard Model of particle physics is true.
Regarding modal terminology, I shall follow Alvin Plantinga in taking a possible world to be a maximal state of affairs (i.e., for any state of affairs A, a possible world either includes or excludes that state of affairs). A book B on world W is a maximal set of propositions, each of which is true at W. So, for any book B on any world W and for any proposition P, either P or ~P is a member of B. Next, I shall assume the truth of S5, which says that if a state of affairs is possible, then its necessarily possible. (A quick example. Take this sentence [let’s call it ‘P’]: ‘At 10:00 am on 21 June 2007, Joe met his girlfriend for coffee at the Starbucks on the Florida State University campus.’ If P is true at some world Wx, then at every possible world it is true that P is true at some world Wx. That is, if P is possibly true, then it’s necessary that P is possibly true.) Finally, by just ‘possible worlds’ (and its cognates) I mean metaphysically possible worlds, and by ‘nomologically possible worlds’ (and its cognates) I shall mean all and only those possible worlds in which the Standard Model is true; that is, (P) is true at all and only nomologically possible worlds:
(P) The Standard Model of particle physics is true.
So much for assumptions and terminology. To the argument!
There are two conceptions of God. On one conception, God has necessary existence, God exists in all possible worlds. Trivially, if God exists in all possible worlds, then the proposition (G) is true in all possible worlds:
(G) God exists.
Thus, for any book B on any world W, (G) is a member of B on W.
Now, consider that if God exists in all possible worlds, then God exists in all nomologically possible worlds. Trivially, if for any nomologically possible world WNx God exists at WNx, then (G) is a member of the book BNx on WNx. (Hereafter, I shall just use ‘BNx’ to mean “book on a nomologically possible world.”) But of course, then, every BNx would also contain (P); and if every BNx contains both (P) and (G), then all such books contain (P&G):
(P&G) The Standard Model of elementary particle physics is true, and God exists.
But if every BNx contains (P&G), then every BNx contains (P6G):
(P6G) If the Standard Model of elementary particle physics is true, then God exists.
In short, then, if God has necessary existence, then even the Standard Model implies his existence. But if any theory with a theological implication cannot be a scientific theory, then the Standard Model of elementary particle physics cannot be a scientific theory!
Now, let’s suppose the philosopher of science mounts a campaign against the necessary-existence conception of God. If God exists in any possible world, she says, his existence is merely contingent. In fact, let us suppose the philosopher of science convinces our mini-ID theorist that not only is God’s existence metaphysically contingent, it’s nomologically contingent: God exists at some nomologically possible worlds, but not all nomologically possible worlds. Heck, let’s even say that our mini-ID theorist assumes agnosticism as to whether or not the actual world is among those nomologically possible worlds at which (G) is true. Does (P) still imply a theological proposition? Yes.
One implied proposition is this:
(E) There exists a possible world Wγ such that (G) is true at Wγ.
If (E) is true, then (E’) true:
(E’) (G) is true at Wγ.
In fact, not only is (E’) true, it is metaphysically necessary. There is no metaphysically possible world at which (E’) is false. Clearly, (E’) is a theological proposition.
Now, suppose that Wγ is identical to the actual world. If so, then (A) is metaphysically necessary:
(A) (G) is true at the actual world.
If (A) is metaphysically necessary, then the book on the actual world contains both (P) and (A), and thus (P&A):
(P&A) The Standard Model of particle physics is true, and (G) is true at the actual world.
But, (P&A) entails (P6A):
(P6A) If the Standard Model of particle physics is true, then (G) is true at the actual world.
If (A) is true, then it’s metaphysically necessary; and if (A) is metaphysically necessary, then it is entailed by the Standard Model of elementary particle physics. But if (E’) is a theological proposition, then so is (A), in which case (P) entails a theological proposition.
If God exists in the actual world, then the Standard Model of particle physics entails that God exists in the actual world, a theological implication if ever there were one. If scientific theories cannot have theological entailments, then if God exists, the Standard Model is not a scientific theory. But surely we want to say that even if God exists, the Standard model is a scientific theory. Therefore, it must not be the case the scientific theories cannot have theological entailments.
In closing, our mini-ID theorist would likely find small comfort in forcing the philosopher of science into admitting that all scientific theories have theological implications should it turn out that God possibly exists, but doesn’t exist in the actual world. True. So, the mini-ID theorist might consider whether she can come up with a scientific methodology in order to discover whether or not the actual world is a member of the worlds at which (G) is true. The present argument is designed (if I may use that term) not to show this is possible, but only to show that the theological implications of a conclusion cannot determine whether or not her project is scientific.
– Joseph Long