Sunday, April 18, 2010

Potential Theistic Explanations: Optimality and its Discontents

This post is part of my discussion of Chapter 5 of Gregory Dawes's book Theism and Explanation that began here and, much to everyone's surprise, continued here.

Dawes's basic goal is to show that there are no good in principle objections to theistic explanations. They can be genuine intentional explanations. It just so happens that they aren't very good explanations.

Chapter 5 of Dawes's book deals with some of the in principle objections. Since the argument is that divine explanations are types of intentional explanation, the proponent must posit a specific divine intention as the explanation of a given state of affairs.

The theological sceptic thinks this is untenable: we cannot know the mind of God. So we cannot offer divine intentional explanations. We saw this last time when looking at Elliot Sober's objection to intelligent design.

Dawes responded to Sober by claiming that we can put some constraints on theistic explanations. We do so by employing the rationality and optimality principles. The optimality principle states that God, because of his divine nature, would always choose the most optimal means to an end.

Dawes thinks this helps to constrain potential theistic explanations. If the theist wants to claim God (G) is the best explanation for something (X), then they have a double burden: (i) they must posit a specific divine goal that would require X; and (ii) they must show that X is the most optimal means to achieving the divine goal.

This is potentially devastating for the theist since it seems obvious to many that the world is imbued with sub-optimality. This would seem to imply that God could not be a good explanation for what we observe.

Thus, some will be inclined to object to this optimality principle. Dawes considers four such objections.

1. God is not Obliged to act Optimally
The first objection derives from certain assumptions about God's agency. It is argued that since God is omnipotent and perfectly free, he is under no obligation to act in an optimal way.

Dawes argues that this objection is misplaced. The optimality principle places a constraint on potential theistic explanations; it does not place a constraint on God. It is an epistemological claim; not a metaphysical or theological claim.

If theism wants to enter the explanatory market, then it has to play by the rules. It has to offer itself up for rational scrutiny along with other explanations. If the response to that scrutiny is that God can do whatever he likes, then theism is inscrutable and cannot be a explanatory thesis.

2. There is no Optimal Action
The second objection begins with some parallels between the idea of the best possible world and the optimal realisation of a divine intention. Surely if we are to claim that X is optimal, we are implying that X is a feature of the best possible world?

The problem with this parallel, according to the objectors, is that the concept of the best possible world is incoherent. Two reasons are offered for this (i) there is no single scale of value and (ii) value is potentially infinite.

These are problems with which utilitarians have long contended. For instance, classical hedonic utilitarians argued that conscious pleasure was the sole measure of value. "Piffle!" replied John Stuart Mill. There is a range of higher pleasures that are not commensurable with the lower pleasures. But if there is no single scale of value, then we cannot establish which is the best possible world.

Likewise, if value comes in units (e.g. utiles) then it is something that you can repeatedly add to (like an infinite set). And if it is infinite, there is no best possible world.

Dawes agrees that these are forceful criticisms but identifies three possible responses.

First, this objection may simply prove the incoherence of theism. After all, the optimality principle seems plausible: if God is omniscient, omnipotent and omnibenevolent, then it seems right to expect him to act optimally. So maybe the problem is not with the acceptability of the optimality principle, but with the very idea of God. Perhaps to speak of perfect goodness is to land ourselves in a conceptual muddle.

Second, Dawes thinks it is possible to reject the parallel between the optimal realisation and the best possible world. The idea here is that optimal realisation is only concerned with specific features of the actual world and not with general features of all possible worlds.

Third, it may be that a comparative judgement is all that is required. In other words, even if we cannot talk about a best possible world, we can talk about a better world. This line of thought is attributed to William Rowe. If Rowe is right, then comparing the merit of different realisations of a divine plan should be a doddle.

3. We Cannot Make Such Judgements
The third objection to the optimality principle stems from modal scepticism. This is something I alluded to in the first post on Dawes's book. The idea is that in proposing an intentional explanation, we assume knowledge of the options that were available to the intentional agent.

So in explaining why you chose chocolate ice-cream, I can imagine the options that were open to you and make certain guesses about why you chose as you did. The problem is that we can't do this when considering God as an intentional agent. We have no idea what options were available to him.

This type of modal scepticism is promoted by Peter van Inwagen, who uses it in responding to the problem of evil. (He rejects the idea that God explains anything; we do not come to know of God's existence through evidence and observation.)

Dawes has a couple of responses to this. First, he argues that a complete modal scepticism is unwarranted. We may not be able to comment on all the options available to God, but we may be able to make some decent comparative assessments.

Second, modal scepticism has devastating implications for the doctrine of divine omnipotence. Omnipotence is usually defined in terms of being able to do what is logically possible. But modal scepticisms implies that we cannot even know what is logically possible. Hence we cannot appeal to divine omnipotence.

4. Intelligent Design is not Optimal Design.
The final objection comes from the intelligent design theorist William Dembski. The official ID-position is that the designer is intelligent, not necessarily divine. So ID is not committed to optimality. Of course, Dembski is a theist, but he thinks that sub-optimality arguments must be dealt with from a theological perspective not a scientific one.

Suppose the theist is challenged by an atheist claiming that the wasteful suffering in the natural world provides evidence against the existence of a theistic designer. Dembski would respond by trying to reconcile God's nature with what we observe. In other words, by constructing a theodicy. This would still not affect our ability to infer design simpliciter.

Dawes thinks that this underestimates the problem. Sure, it is possible to reconcile God's existence with wasteful suffering, but this only works on the presupposition of God. It is not possible to infer the existence of God from a sub-optimal natural world.

In other words, unless we specify the divine intention and adopt the optimality constraint, we must concede that theism is not in the explanatory game.

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