Read Where the Conflict Really Lies: Science, Religion, and Naturalism Online
Authors: Alvin Plantinga
Tags: #Non-Fiction, #Biology, #Religious Studies, #Science, #Scientism, #Philosophy, #21st Century, #Philosophy of Religion, #Religion, #v.5, #Amazon.com, #Retail, #Philosophy of Science
Construed in this way, Paley is not proposing an argument; he is instead directing our attention to the way we are inclined to form design beliefs in certain circumstances, and trying to get us into those circumstances by describing in detail what those “contrivances of nature” are like; he is trying to get us to recall design beliefs, and put us in situations in which we form design beliefs. What should we call this activity? There is no familiar name; I’ll just speak of design
discourse
as opposed to a design argument.
Now the fact is, of course, that Paley wasn’t thinking of this distinction between design arguments and design discourses, and plumping for the latter. What he says sometimes sounds like a design
argument (often like an argument from analogy) and other times like a design discourse. We need not try to decide which interpretation fits Paley better; that doesn’t really matter for my purposes. What I mean to stress, here, is that there are these two possibilities: there are non-argumentative design discourses as well as design arguments. Note further that the recognition of non-argumentative design discourses fits in well with the way in which we typically form beliefs about other minds. Indeed, insofar as design entails mental states on the part of some other person (the designer), the belief that a given object has been designed
is
a mental state-ascribing belief. If our other beliefs about minds, the mental states of others, are formed in that basic way, it is not implausible to suppose that the same goes for this sort of belief. The idea would be, therefore, that when you are on that walk with Paley and encounter a watch, you don’t make an
inference
to the thought that this object is designed; instead, upon examining the object, you form the belief in that immediate or basic way. The same goes if you are on a voyage of space exploration, land on some planet which has an earth-like atmosphere, but about which nothing or next to nothing is known, and come across an object that looks more or less like a 1929 Model T Ford. You would certainly see this object as designed; you would not engage in probabilistic arguments about how likely it is that there should be an object like that that was not designed. You might also encounter something that was obviously designed, but such that you had no idea what its function was; you don’t have to know what the function is in order to perceive that it has been designed by a conscious, intelligent agent.
IV THE DIFFERENCE IT MAKES
“Well,” you say, “perhaps we could think of these situations where we form design beliefs along the above lines, but so what? Why should
that be of any particular interest?” I think it
is
of interest, and in fact of very considerable interest. First, the suggestion is that you come to form design beliefs, at least on some occasions, in the basic way. If so, the belief in question can have warrant or positive epistemic status, indeed, a great deal of warrant or positive epistemic status for you, even if you don’t know of any good argument from other beliefs for the belief in question—even, indeed, if there
aren’t
any good arguments of that sort. As we’ve seen, this is how it goes with our beliefs about the mental states of others; but the same goes for our perceptual beliefs.
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The same also goes for our beliefs about the past; as Bertrand Russell pointed out, it is consistent with our evidence that the world, complete with its crumbling mountains, wrinkled faces, and apparent memories, popped into existence five minutes ago.
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In all of these cases, it is exceedingly hard to find good arguments for the conclusions in question; but surely you often do know such things as that the flowers in the backyard are blooming, or that Martha is thinking about what to make for supper, or that you went for a walk earlier this afternoon. Perhaps the same goes for design beliefs; perhaps one can’t find a way of formulating much of an argument for the conclusion that hearts, for example, are designed, even though the belief to that effect, formed upon seeing how they are constructed and how they work, has a good deal of warrant.
Secondly, there is a difference here in the way in which the beliefs in question can be criticized, or refuted. Beliefs formed in the basic
way are not, of course, immune to criticism. To return to an example from
chapter 6
, I look into a field, see what looks like a sheep, and form the belief that there is a sheep in the field. You, whom I know to be the owner of the field, come along and tell me there are no sheep in that field, although the field is frequented by a dog which from this distance is visually indistinguishable from a sheep. Then I have a
defeater
for my belief, even though that belief was formed in the basic way.
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Another example: I believe on the basis of my guidebook that King’s College in Old Aberdeen, Scotland, was founded in 1595. I form this belief in the basic way; I don’t reason as follows: this is a reputable guidebook; reputable guidebooks are usually right when they give the date of a College’s founding; therefore…. But then I learn that this particular guidebook is unreliable in most of what it says about Scottish universities; this gives me a defeater for that belief about the foundation of King’s College, and I will no longer hold it.
A belief formed on the basis of an argument, however, can be criticized in a different way as well. When you (properly) form a belief on the basis of argument, what typically happens is that warrant or positive epistemic status is transferred from the premise belief(s) to the conclusion. Consider, for example, Euclid’s
reductio ad absurdum
argument for the proposition that there is no greatest prime. Suppose there is a greatest prime and call it n; now multiply together n and all the prime numbers smaller than n and add 1: call this number p. Clearly p is not evenly divisible by n or any prime smaller than n; hence p is prime and greater than n; hence n is not the greatest prime after all; so there is no greatest prime. Suppose I form my belief that there is no greatest prime on the basis of this argument. If my belief has warrant, it acquires warrant by way of warrant-transfer from the premises, for example the premise that if a set S includes only primes, then the product of all those primes plus 1 will not be evenly divisible
by any member of S. A belief formed in that way, as the conclusion of an argument, can be criticized in terms of the cogency of the argument. We can ask whether the argument is valid, i.e., whether the conclusion really follows from the premises; we can also ask whether the premises are true; we can also ask whether the argument is circular, or begs the question, or is in some other way dialectically deficient. None of these sorts of criticism is relevant to beliefs formed in the basic way. And this makes an important difference with respect to our discussion of modes of forming design beliefs.
Turning back to Paley, as we saw, we can construe him either as giving a design argument, or as giving a design discourse. Now in what way can such a discourse fail: how can a design discourse be shown to be unsuccessful? Well, of course one way would be to show, somehow, that the design discourse fails to produce any tendency to form the relevant design belief. But there is also another way. A basic belief can be subject to defeaters: one way, therefore to argue that a design discourse is unsuccessful would be to show that the design belief formed in this way is in fact subject to defeat. This would be a matter of producing a defeater for the design belief—that is, getting a person who holds a certain design belief to accept another belief D such that she can’t sensibly continue to hold the design belief, as long as she holds the defeating belief D. In this case, what would do the trick is a belief such that once you held
that
belief, you could no longer accept the conclusion of Paley’s design discourse—for example, that the eye has been designed by an intelligent and powerful being. Such a defeater could take two forms.
On the one hand, you might become convinced that as a matter of fact the eye was
not
designed, but came to be in some other way. Then you would have a
rebutting
defeater: you come to believe a proposition that you see is incompatible with the proposed defeatee.
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That’s the sort of defeater I acquire in the example above about the dog I mistake for a sheep; based on your testimony, I acquire the belief that there are no sheep in that field. On the other hand, I might acquire an
undercutting
defeater. This would happen, roughly, if I come to believe something that undercuts or nullifies or negates my reason for the proposed defeatee. For example, you might have told me not that there were no sheep in that field, but only that a dog who is a sheep lookalike often frequents the field. Then my reason for thinking there is a sheep there would be undercut, and I’d no longer believe that proposition. Still, I would not form the belief that there
weren’t
any sheep in that field: what I saw could have been a sheep even if that dog is in the neighborhood (and also, perhaps there were sheep in parts of the field I couldn’t see). It’s worth noting that undercutting defeaters come in degrees: rather than bringing it about that I can no longer rationally hold the belief in question, they can bring it about that I can no longer rationally hold that belief as
firmly
as I did. For example, Mic and Martha tell me they saw you at the party; I believe, naturally enough, that you were at the party; then Mic tells me he didn’t see you there, but was just relying on Martha’s testimony. This partially undercuts my reason for thinking you were there; I may continue to believe that you were, but I will believe this less firmly.
Now Darwin is often credited with having
refuted
Paley’s argument. Translated into the present context, this would be the claim that Darwin has provided a defeater for the design beliefs to which Paley calls our attention. How would that go? Some writers seem to believe that Darwin, or current evolutionary science, has provided a
rebutting
defeater: they believe that evolutionary science has shown that as a matter of fact eyes and other biological structures have
not
, in point of sober truth, been designed. As we saw in
chapter 1
, Richard Dawkins believes contemporary evolutionary science “reveals a universe without design”; and in
chapter 2
, we saw
that Daniel Dennett apparently thinks current evolutionary science includes the claim that this process is unguided. If either of these were correct, and if current evolutionary science is successful, then current evolutionary science would have provided a rebutting defeater for design beliefs. Current evolutionary science would have given us sufficient reason to believe the
denials
of these design beliefs—that is, sufficient reason to believe that these biological structures have
not
been designed. As we also saw Dawkins’s argument for this conclusion, however, is unsound
in excelsis
; and Dennett, for his part, simply assumes without argument that current evolutionary theory includes the proposition that the process of evolution has not been guided (by God or anyone else), despite the fact that this proposition looks much more like a metaphysical or theological add-on than a part of the scientific theory as such.
What current Darwinian evolutionary theory shows, if successful, is that the living world with all its apparently designed structures has come to be by way of natural selection operating on something like random genetic mutation. Well, suppose they did come to be in this way. Would that show that Paley’s design beliefs—for example, that the human eye was designed—was mistaken? Of course not. As we saw earlier, God (or other beings he has created) could have planned, superintended, and guided this process. Indeed, he (or they) could have been more intimately involved in it: he could have
caused
the relevant genetic mutations. God might have caused the right mutations to arise in the right circumstances in such a way as to bring it about that there exists organisms of a type he intends; the organisms resulting from this kind of evolution would be designed, but also a product of natural selection working on random genetic mutation.
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So even if (contrary to fact) either Darwin or more recent biology were to have actually shown that the biological structures in
question
have
come to be by way of these Darwinian mechanisms, it wouldn’t follow that they have not been designed; therefore they do not provide a rebutting defeater for Paley design beliefs or a problem for Paley’s design discourse.
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To provide a rebutting defeater here, Darwinian science would have to show that the biological phenomena in question have been produced by
unguided
Darwinian evolution. But (naturally enough) they haven’t shown that evolution
is
unguided by God or any other intelligent agent; that wouldn’t be the sort of thing, one supposes, within the capability of empirical science.
Does Darwinism provide an
undercutting
defeater for the design belief? How would it do a thing like that? Perhaps as follows: “It was Darwin’s greatest accomplishment to show that the complex organization and functionality of living beings can be explained as the result of a natural process, natural selection, without any need to resort to a Creator or other external agent.”
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Putting this another way, Darwinian science could perhaps show that it is
possible
that the structures and traits in question have come to be by way of unguided evolution. It wouldn’t be necessary to show that they actually
did
come to be by way of unguided evolution; it would suffice to show that it
could have
happened that way. So the idea would be to show that the eye, for example, could have come to be by Darwinian evolution, unguided by the hand of deity (or other intelligent agents). Of course bare
logical possibility
is not enough: it is logically possible that the horse, say, sprang into being from the unicellular level (bacteria, perhaps) in one magnificent leap. What the Darwinian has to show, to provide a
defeater, is an unguided evolutionary path which is not
prohibitively improbable
. Have Darwinians actually accomplished this? Have they shown, for example, that it is not prohibitively improbable that the mammalian eye has developed in this way from a light sensitive spot?