Modality and Probability

On p. 51 of Where the Conflict Really Lies, Plantinga says: “[T]he probability of a contingent proposition on a necessary falsehood is 1.”

So, where C = a contingent proposition and F = a necessary falsehood, Plantinga is saying P(C|F)=1.

This seems false. How are we getting our values? If we understand conditional probability to be defined as:

p

and we grant that a necessary falsehood has the probability of 0, then P(C|F) ≠ 1, rather, it is undefined. Shoenberg, “If P(A) = 0, then P(B|A) is undefined, just as division by zero is undefined in arithmetic. This makes sense, since if event A never happens, then it does not make much sense to discuss the frequency with which event B happens given that A also happens” (Introduction to Probability with Texas Hold’em Examples, Chapman and Hall, 2011, p.40). After some further investigation, I noticed that Tyler Wunder gives a similar objection here.

However, the above is too quick.
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God’s Freedom

Sometimes it is said that God has libertarian freedom. The argument for this often goes like this:

  1. God freely chose to create the world.
  2. The world is not necessary.
  3. Therefore, God’s free act of creating of the world was not determined.
  4. Therefore, God has libertarian freedom.

This argument is actually quite popular, but it is invalid. For the sake of the argument, I’ll grant we can validly get to (3). However, the jump to (4) assumes a suppressed premise, something like:

    3a. If a free act A is not determined, then A is libertarian free.

But that is false. It assumes that indeterminism is sufficient for libertarianism, when it’s actually only necessary for libertarianism. What is needed instead is something like this:

    3a′. Freedom is incompatible with determinism.

But with this addition, the argument would then assume incompatibilism. (1)–(2) at best get you indeterminism, but what is needed to secure the conclusion that God’s freedom is libertarian is an argument for incompatibilism, not an argument that assumes incompatibilism.

From Skeptical Theism to Skeptical IBEism

Skeptical theism is, roughly, a strategy that employs would-be facts about our cognitive limitations and applies them to various atheological arguments from evil against the existence of God.

Inference to the best explanation (IBE hereafter) is, roughly, the type of inference in which one derives the conclusion that explains the available evidence best.

Skepticism about IBE, is, roughly, the view that the above type of inference is not trustworthy to lead us to truth.

I wonder if accepting skeptical theism puts any pressure on the one who accepts it to also accept skepticism about IBE. That is, should the skeptical theist become a skeptical IBEist? In this blog I’ll try to sketch some flat-footed reasons for thinking so. The literature on both topics is large and complicated, and so I’m really wondering if the below argument warrants further inspection, that is, whether there is even a prima facie push for the skeptical theist to become a skeptical IBEist. Of course, some have argued that skeptical theism implies something like Cartesian skepticism. If that’s true, then skepticism about IBE follows quickly enough. But that’s a strong claim, I’m going for something far more modest—though, as I will suggest, if my worry is real, there will be unpleasant enough consequences, at least for some Skeptical theists. (more…)

Jonathan Edwards and Necessity

I. Introduction

A friend wondered if I could say something more about the charge that Edwards commits a modal fallacy—in this case, it is alleged that from 1. necessarily, if α then β, 2. α, he concludes, 3. necessarily β—in the course of his argument for determinism (see this post for context). Specifically, he wondered if I might cite more from Edwards. In this post I’ll quote one of Edwards’ arguments for the necessity our actions have, and his reasoning should make clear that the charge leveled by some—namely, Richard Muller, some associated with the Uterecht school, and (some of) their students—is simply not viable. Some of this will be a repetition of my last post, but I view what follows as a more decisive response to Muller et al., than my previous post. (more…)

Myth Busters: Jonathan Edwards Committed a Modal Fallacy

Introduction

You may not be attracted to Jonathan Edwards’ particular model of determinism and compatibilism. Such is fine. You may think you have good reasons to reject his system. Perhaps you do. But, that he commits an elementary fallacy in modal logic—confusing the necessity of the consequence with the necessity of the consequent—should not be one of those reasons. Unfortunately, this charge against Edwards is all-too-common. More unfortunately, it seems to come only from the pens of ostensibly Reformed theologians—who are allegedly friendly interpreters of Edwards. On the other hand, open theists like William Hasker seem to be more charitable to Edwards (cf. Hasker, God, Time, and Foreknowledge, 1989, 72). In this post I’ll explain why I think Edwards is innocent of such a charge.

Before continuing, let me explain the fallacy under discussion so that we can have it under our belts as we move forward: (more…)

Getting Clear(er) on Reformed Theology, Determinism, and Necessity

Recent conversations have again turned my attention to claims by Muller and the Utrecht school, to the effect that “Classic Reformed theology is not a species of determinism.” I find most of the substantive conclusions they draw perplexing. Aside from the fact that it is a live and open debate whether the intellectual progenitor(s)—whether Aristotle, Aquinas, or Scotus—of putative classic Reformed theologians were compatibilists or not, is that I have a hard time seeing how their conclusions follow even given what they say about the views of the classical Reformed theologians. (more…)

Libertarian Free Will and the Atonement

Here’s a worry. The claim that “Christ died for our sins” (I Cor. 15:3) is something on which virtually all Christians agree. Many think this claim is at the heart of the Christian faith. Suppose you think that Jesus died for your particular sins, which seems to be a fairly popular pre-theoretical view. Then, we might wonder how we can avoid (in a strong, libertarian sense) doing those specific sins. If we cannot, then it would seem that (one aspect of) the atonement rules out our having libertarian free will. Of course, this wouldn’t deal a knockout blow to the conjunction of Christianity and libertarian free will. It would mean, however, that Christians who affirm libertarian free will could not affirm that Jesus died for our particular sins. But, not only does it seem possible that Jesus did indeed die for our particular sins (and holding to libertarian free will would commit you to its necessary falsehood (in saying this I am assuming some modal moves that I don’t spell out here)), rejecting such a notion means rejecting what I take to be a fairly common and wide-spread belief, one which many Christians who hold to libertarian free will have also held. This would be, if not ad hoc, at least a previously unnoticed cost of “free will theism.” Let me flesh this out a bit. (more…)