The Argument from the Psychological Relevance of Logical Laws

Introduction

In his book C.S. Lewis's Dangerous Idea: In Defense of the Argument from Reason, Victor Reppert lists nine presuppositions of rational inference.

1. States of mind have a relation to the world we call intentionality, or about-ness.

2. Thoughts and beliefs can be either true or false.

3. Human beings can be in the condition of accepting, rejecting or suspending belief about propositions.

4. Logical laws exist.

5. Human beings are capable of apprehending logical laws.

6. The state of accepting the truth of a proposition plays a crucial causal role in the production of other beliefs, and the propositional content of mental states is relevant to the playing of this causal role.

7. The apprehension of logical laws plays a causal role in the acceptance of the conclusion of the argument as true.

8. The same individual entertains thoughts of the premises and then draws the conclusion.

9. Our processes of reasoning provide us with a systematically reliable way of understanding the world around us.[1]

Commenting on this list of presuppositions, Reppert writes, "It seems to me that all of these elements of reasoning are prima facie difficult to fit within the framework of philosophical naturalism."[2] Here I want to quickly sketch how I would assess one of Reppert's supporting arguments for that claim.

Reppert's Atheistic Argument for Violence

Victor Reppert recently posted the following blog post, which I quote in its entirety.

An atheistic argument for violence:
1) Atheism is true, and so obviously so that religious believers must be insane.
2) Insane people can do outrageous things.
3) The people who promulgate belief in God are putting other people's sanity in danger.
4) Even if we have to forcibly stop them from doing so, we can prevent them from leading other people on the road to insanity, and hence possibly outrageous actions.
5) Therefore, the use of force in the name of suppressing religion is justified.

Victor Reppert on the Argument from Evil as a Reductio

[This post was originally published on The Secular Outpost on June 12, 2012 and then republished on February 22, 2016. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date. The link was also updated to its current location.]

(Redated post originally published on 12 June 2012)

Can atheist who rejects moral realism press the argument from evil? Many theists, including William Lane Craig and Ravi Zacharias, have argued that the answer is "no." In my old critique of one of Zacharias's books, I wrote the following.

Zacharias presents two objections to AE. First, he suggests that it is incoherent for atheists to appeal to evil as evidence of the nonexistence of God since objective moral evil could not exist if there is no God (p. 48). Yet, as I argued above, objective moral values are logically possible even if there is no God. And the atheist need not postulate the existence of objective moral values in order to use evil as evidence for atheism. An argument from evil might not contain any normative premises; the atheist could appeal to God's loving nature rather than God's moral nature.[13] For example:

(1) If a perfectly loving God were to exist, then he would not permit the occurrence of any unjustifiable suffering.
(2) But unjustifiable suffering does occur.
(3) Therefore, a perfectly loving God does not exist.

To emphasize the point (though I consider this unnecessary), the atheist might even change the name of the argument from "the Argument from Evil" to "the Argument from Unjustifiable Suffering."[14]

Most importantly, AE may be understood as a challenge to the internal coherence of a theistic worldview. An AE can be understood as saying something like the following:

Look. You theists believe that X, Y, and Z are evil. You theists believe that God is good. You theists believe that good persons are opposed to evil. So you theists need to explain why a god who is good (in your sense of 'good') would allow so much apparently pointless evil (in your sense of 'evil'). If you can't explain it, then that is a problem for the internal coherence of your worldview.[15]

When AE is understood in this way, it doesn't presuppose that there are objective moral values.

In an old post, Victor Reppert says that he is aware of running the argument from evil as a reductio ad absurdum argument, but he is unconvinced. He writes:

I still maintain that important phenomena that give rise to the problem of evil are themselves deeply problematic for naturalism, including consciousness, objective moral values (and yes I know all about running it as a reductio without presupposing objective moral values--I still think subjectivism undercuts the argument).

Here's my question to Reppert: why? How does subjectivism undercut the argument? For example, how does subjectivism undercut Draper's version of the evidential argument from evil (summarized here)?

The Evidential Argument from Mind-Brain Dependence: A Reply to Bilbo

[This post was originally published on The Secular Outpost on November 26, 2006. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date. The link was also updated to its current location.]

In my response to Victor Reppert's anti-naturalistic argument from pain, I stated that a more specific fact (consciousness is dependent upon the physical brain) about consciousness is antecedently more likely on naturalism than on theism. Bilbo provided several feedback messages in response to this claim. As I read him, he thinks the argument is no threat to Christian theists. It is apparently his view that mind-brain dependence is at least as probable on Christian theism as on naturalism, since Christian theists believe in specific, sectarian doctrines that raise the probability of mind-brain dependence. Since I think Bilbo is wrong about this, I'll explain why.

First, here is the logical form of my evidential argument.

Let D = the mind is dependent upon the physical brain.
Let T = classical theism
Let N = metaphysical naturalism

(1) D is known to be true.
(2) T is not much more probable intrinsically than N.
(3) Pr(D/N) > Pr(D/T).
(4) Other evidence held equal, T is probably false.

Note the modest nature of this argument. It doesn't claim that theism is probably false; it merely claims that evidence (D), by itself, favors N over T. This distinction is crucial since it allows for the possibility that there could be other evidence that both favors T and outweighs the evidence for N provided by D. Thus, D should be understood as a prime facie reason for rejecting T.

Let me now turn to some of Bilbo's specific comments.

Bilbo: "My first problem is that it seems more accurate to say that minds *are* the physical brain on Naturalism (not merely dependent on them). And since this has not been demonstrated, it would beg the question to assert that the postulate that "minds are the physical brain" provides evidence for Naturalism."

That would indeed beg the question, which is why I never said that! My argument is an inductive argument. It would be illegitimate to state the evidence in such a way that entails the hypothesis to be proved. Therefore, I'll stick with my original formulation of the premise ("the mind is dependent upon the physical brain").

Bilbo: "But the Christian views I mentioned also make it antecedently probable that minds will be dependent on the brain. Let's use the structure of your argument with Christian non-reductive physicalism (hereafter NRP)..."

If theism is improbable given D, then so is Christian theism (or any other more specific belief system that entails theism). Christian theism entails theism; therefore it cannot be more probable than theism. Premise (4) entails that, other evidence held equal, Christian theism is probably false.

I don't deny the potential relevance of sectarian doctrines to the issue of whether my argument is sound. They could raise Pr(D/T) or lower Pr(D/N). In order to assess the evidential significance of such doctrines, we would need to apply a principle that Draper calls the "weighted average principle" (WAP). Let H represent some Christian doctrine. Then WAP can be represented as follows.

Pr(D/T) = Pr(H/T) x Pr(D/T&H;) + Pr(~H/T) x Pr(D/T&~H)

This formula is an average because Pr(H/T) + Pr(~H/T) = 1. It is not a simple straight average, however, since those two values may not equal 1/2.

Let us consider, then, Christian non-reductive physicalism (CNRP), which Bilbo proposes as a specific doctrine that he believes raises the probability of D given (Christian) theism. Bilbo defines CNRP as "the non-existence of all supernatural beings, except for those that are or were at some point divine (angels, demons, God, etc.)." Bilbo claims that CNRP "entails the nonexistence of disembodied human minds." Using WAP, we obtain the following.

Pr(D/T) = Pr(CNRP/T) x Pr(D/T&CNRP;) + Pr(~CNRP/T) x Pr(D/T&~CNRP)

In order to reject my evidential argument, therefore, Bilbo would need to show that CNRP raises Pr(D/T) so that it is greater than or equal to Pr(D/N) by using the above formula. Does CNRP do that? I shall leave the question as an exercise for the reader.

(Note: I have borrowed heavily from ideas in another paper by Paul Draper, "More Pain and Pleasure: A Reply to Otte." I am, of course, responsible for any errors in my post.)

Victor Reppert's Anti-Naturalistic Argument from Pain

[This post was originally published on The Secular Outpost on November 25, 2006 and then republished on February 11, 2016. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date. The link was also updated to its current location.]

There are a variety of approaches to formulating an argument from evil against theism. Two of the most influential versions of the evidential argument from evil were developed by atheist William Rowe and agnostic Paul Draper. Both involve appeals to pain. In a recent entry on his blog, Victor Reppert tries to turn the tables on proponents of arguments from evil (pain) by arguing that pain is a problem for atheists. Reppert formulates his argument against naturalism as follows.

1. If naturalism is true, then consciousness does not emerge.
2. If consciousness does not emerge, then pain does not exist.
3. Therefore, if naturalism is true, then pain does not exist.
4. Pain exists.
5. Therefore, naturalism is false.

Notice that premise (1) of the above argument entails that naturalism and consciousness are logically incompatible. Reppert's argument may be reasonably characterized, then, as a very specific example of a logical argument from consciousness against naturalism (as opposed to an evidential argument from consciousness as defended by Richard Swinburne). I believe this characterization is further supported by Reppert's statement, "the actual internally experienced state of pain is a huge, hard problem for atheistic naturalism, a problem that I personally consider to be logically impossible to solve."

Does Reppert literally mean what he says? As a so-called logical argument against naturalism, it isn't clear to me why this argument is in any way an improvement over logical arguments from evil against theism. In particular, Reppert has not yet presented a defense of (1) in its current form (i.e., lacking some sort of probabilistic hedge).

Perhaps, however, Reppert did not intend for his argument to be worded so strongly. Instead, he might say, we should understand his argument as an evidential argument against naturalism. If so, it seems to me that Reppert's argument from pain violates the Rule of Total Evidence. Allow me to explain. Let us assume, for the sake of argument that Reppert is correct that consciousness is antecedently more likely on theism than on naturalism. Furthermore, as Reppert points out, pain presupposes consciousness. It doesn't follow from these two assumptions, however, that the statement, "The kinds and distribution of pain we find in the world is epistemically more probable on naturalism than on theism," is false.

Here's why. Reppert has committed the fallacy of understated evidence. In general terms, we could say that Reppert has identified some general fact F (consciousness exists) about a topic X (consciousness) that is antecedently more likely on theism than on naturalism. It could still be the case that a more specific fact (S) about X is antecedently more likely on naturalism than on theism. As Paul Draper writes, "we know a lot more about phenomenal consciousness than just that it exists" ("Partisanship and Inquiry in the Philosophy of Religion," unpublished paper). Draper then gives an example of a more specific fact about consciousness, a fact that, given consciousness exists, is more probable on naturalism than on theism. As Draper explains, we also know from neuroscience that the mind is dependent upon the physical brain, a fact that is more likely on naturalism and consciousness than on theism and consciousness. Thus, as Draper concludes, "when the available evidence about consciousness is fully stated, it is far from clear that it significantly favors theism."

Reppert on Drange vs. Wilson

[This post was originally published on The Secular Outpost on February 17, 2006. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date.]

Victor Reppert here provides an assessment of the Drange-Wilson debate on the existence of the Christian God.

Link: Is Michael Martin's Position in ATHEISM: A PHILOSOPHICAL JUSTIFICATION inconsistent?

[This post was originally published on The Secular Outpost on January 23, 2006. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date.]

LINK