Blogging Alex Rosenberg's The Atheist's Guide to Reality, Chapters 3 & 4

1. What Rosenberg means when he asserts that there is no purpose in nature is essentially correct. But it’s hard to avoid language that suggests otherwise (cf. #6, infra). There are natural functions–the heart has the purpose of pumping blood–and there are things such as human beings that do things for reasons, but all this is explained (even if quite indirectly) in terms of natural selection, which is purely mechanical, blind, purposeless: efficient, not final, causation. (But for the mysterious phenomenon of non-locality in the quantum domain, I assume that we’d be entitled to say without hesitation that the natural world is mechanical through and through.)

However, (as noted earlier) Rosenberg ignores the well-known distinction between purpose in and purpose for nature. There might, or might not, be an explanation of why this world in which there is no built-in teleology exists, and that explanation might, or might not, be teleological. God, we theists say, created this universe for a purpose and this, on its face, is independent of whether this thing that he for some purpose created is purely mechanical or instead embodies teleology.

E.g., when after close examination of the casino’s roulette wheel we conclude that its output embodies no purposeful pattern, that the series of numbers that come up do so randomly and mechanically. Nonetheless, the roulette wheel exists to make money for the casino’s owner. There’s purpose for it but not in it (assuming it’s not rigged.) From the assumption that the universe (or multiverse) is not God’s creation one may reasonably infer that there is no purpose for it, but there’s no obvious inference from there being no purpose in it to there being no purpose for it and thus no creator. It’s fair enough for Rosenberg to say that if there’s no God then there’s no purpose for nature. His avowed purpose is not to argue against belief in God, but to exhibit the implications of atheism. But he’s mistaken to offer the absence of natural teleology as an argument against there being a purpose for nature.

From the perspective of Christian faith, the question is whether, given the revealed purposes for which God created it, we should expect something other than the non-teleological world Rosenberg describes.

2. Rosenberg writes, “…nothing more powerfully threatens theism than an explanation that meets Kant’s challenge [to explain biological adaptation without invoking design.]” This is false, because on the one hand this kind of explanation does not threaten theism at all, and on the other, because other things do threaten it, e.g., apparently gratuitous evil, but it’s interesting since it’s a view he shares with many theists. It doesn’t threaten theism because it does not threaten Christian theism, which is the most reasonable version of theism, in part because the scientific world picture, including Darwinianism, is likely in light of it.

If the only, or one of the few, good reasons for theism involved explicitly invoking God to explain adaptation, then Darwin’s success threatens theism. So far as theism is concerned, God acts by secondary causation as well as directly, and the fact that some general feature of the world, e.g., speciation, can be explained naturally, presents no challenge at all. (It may, of course, present problems for specific things some theists believe, e.g. that some or all species were created directly, miraculously, or that God specifically designed all the species, or humans—that conflicts with God creating species by secondary causes when that causation is indeterministic.) Prior to Darwin it seem plausible to almost everyone that adaptation had no natural explanation, and miracles were invoked to fill the explanatory gaps, but this tells us something about the limits of the pre-Darwinian imagination, not that there is no creator. If Rosenberg advanced an argument that a God would not create species adapted to their environments by some natural process, or not by the natural process Darwin discovered, that would be fine, but here he takes the easy way, granting what his opponents say when he should know they’re wrong.

3. Here (in Chapter 4) Rosenberg makes a central issue explicit. He asserts that the second law (of thermodynamics) makes reconciliation between theism and Darwin’s discovery logically impossible. Theists try to reconcile belief in a creating God with Darwinian evolution by appealing to the idea of secondary causation. The natural processes described by science in general and Darwin in particular are the means by which God created living things. Rosenberg sees this as a dodge, a hopeless attempt “to have our Darwinian cake and eat evolution too.” For the evolutionary process is probabilistic—this is the force of his reference to the second law—and thus cannot reasonably be used to realize specific creative intentions. If nature were deterministic, theists could claim that God created the various species by means of evolutionary processes, since they would infallibly realize whatever detailed divine plan God had in mind. However, the evolutionary process is not deterministic, so biological adaptation is not the product of divine design. In my view, Rosenberg is right about this: in our indeterministic world, evolutionary theory precludes divine design.

I’m somewhat puzzled by Rosenberg’s pervasive reference to the second law. I’m thinking that if the fundamental laws of nature (quantum mechanics or whatever) are deterministic, then the probability that thermodynamics introduces is just epistemic, not built into nature itself. If those laws are indeterministic, then there’s no need to invoke thermodynamics to secure the outcome that nature is indeterministic, through and through.

4. But he is wrong to think that theism implies divine design. Whatever the case might be with theism considered generically, or with others kinds of theism, Christian theism does not imply it. In fact, to take seriously God’s revealed purposes in creating is to accord a higher prior probability to the secondary causes by means of which God achieves his ends being indeterministic than to his having created a deterministic universe. Rosenberg rightly points out that the natural processes being indeterministic is at odds with God having specific aims in creation, but he poses a false dichotomy when he says that either God created for no purpose or he had specific purposes. God, like anyone else, can do things with general aims in view while leaving the specific outcome to chance or to what others choose to do. Anyone whose aim is the existence of persons truly distinct from himself, persons with whom a genuine personal relation is possible, will bring them into existence by such “chancy” means, rather than acting on a fully specified design plan.

I suppose that we should not blame Rosenberg for having no sense of what is central to the Christian faith: that God’s aim is to bring persons distinct from himself into loving fellowship with their creator, to share in his triune life, and that whatever we say about creation, or about divine omniscience, must be said in light of this. It is sad how many Christians seem just as oblivious, and defend the idea that God must have specifically designed living things, despite the weight of evidence to the contrary.

4. Some biological structures are adaptations: they were naturally selected for in the process of evolution. To deny that there are, in this sense, natural functions, seems perverse. We need to make distinctions like, “The function of the heart is to pump blood but not to make a sound; that thumping sound is just a byproduct of what it was selected for.” Whether we should go on to speak of such things in terms of purpose seems to me not a particularly significant matter. Some worry that purpose cannot be separated from its longstanding association with foresight, intention, and intelligence, but we need some way to mark the distinction, and to speak of purposes seems very hard to avoid.