Divine command theory
March 4, 2011 — 13:19

Author: Alexander Pruss  Category: Divine Command  Tags: , , ,   Comments: 12

The following simple and valid argument came out of discussions with Mark Murphy (who has a forthcoming book that contains related arguments, though perhaps not this one).

According to the identity version of Divine Command Metaethics (IDCM), to be obligated to A is to be commanded to A by God (or to be willed to A by God or to be commanded to A by a loving God–details of this sort won’t matter). But:

  1. If p explains x’s being F, and to be F is the same as to be G, then p explains x’s being G.
  2. My being commanded by God to follow Christ explains my being obligated to follow Christ.
  3. It is not the case that my being commanded by God to follow Christ explains my being commanded by God to follow Christ.
  4. Therefore, it is false that to be obligated to A is the same as to be commanded by God to A. (By 1-3)

And so IDCM is false.

The argument more generally shows that no normative-level answer to a “Why am I obligated to A?” question can provide a property identical with being obligated. Thus, sometimes at least the answer to “Why am I obligated to A?” is that Aing maximizes utility. Hence, by an exactly parallel argument, being obligated to A is not the same as having A as one’s utility maximizing option.

The argument is compatible with constitution versions of DCM on which the property of being obligated to A is constituted by the property of being commanded to A. But such theorists then have the added complication of explaining what the constitution relation means here, over and beyond bidirectional entailment (after all, many non-divine-command theorists will agree that necessarily x is obligated to A iff God wills x to A).

Sceptical theism and the undercuts-our-moral-life objection
February 17, 2009 — 21:12

Author: Alexander Pruss  Category: Problem of Evil  Tags: , , , ,   Comments: 15

Let’s grant that if sceptical theism is true, then for any evil E, we have no reason to think that the prevention of E will lead to an overall better result than letting E happen, so the fact that we do not see God preventing E is not evidence against the existence of God, since we have no more reason to think that God would prevent E than that he would not. The standard objection is that then we have no reason to prevent E, since we have no reason to think that the overall result will be better if we prevent E.

This objection is mistaken. Suppose I offer you a choice of two games–you must play the one or the other. Each game lasts forever. In Game A, you get pricked in the foot with a thorn on the first move. In Game B, nothing happens to you on the first turn. And that’s all you know. (You don’t know if God exists or anything like that.) Which game should you choose?

You should probably say you have the same probability of doing better by playing Game A as by playing Game B. Why? Well, let Games A* and B* be Games A and B minus their first steps. You know nothing about Games A* and B*. (You don’t know if the first step is a sign of what it is to come, or maybe the sign of the opposite of what is to come, or completely uncorrelated with what comes later.) Now given a pair of infinitely long games about which you know nothing, the overall difference in outcome utility can be minus infinity, plus infinity, undefined, or finite. The likelihood that this difference would be within a pinprick is zero. But if the difference is not within a pinprick, then A is better than B iff A* is better than B*, and B is better than A iff B* is better than A*. Since we know nothing about A* and B*, we should not say that it’s more likely that A* is better than B*, nor the other way around. So, the probability that A would give a better result than B is the same as the probability that B would give a better result than A. (This calculation assumes Molinism. Without Molinism, it only works for deterministic games, or as an intuition-generator.)

Now if the reasoning in the anti-sceptical-theism argument is sound, you have no reason to choose Game B over Game A, since you have equal probabilities of doing better with A as with B. But in fact, despite this equality, you should choose Game B. For since you know nothing about what Games A* and B* are like, the expected value of Games A* and B* should be the same–even if it’s infinite, or even if it’s undefined. (Think of doing this with non-standard arithmetic.) So you have two options: first a pinprick, and then something with a certain (perhaps undefined) expected value; or just something with that same (perhaps undefined) expected value. And of course you should choose the latter–you should avoid the pinprick. The lesson here is that while beliefs are guided by probabilities, action is guided by expected values.