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#589 Moral Knowledge and God’s Existence

July 29, 2018

Hi Dr. Craig,

First off, I just want to thank you for the life-changing work you've done, which has been decisive in my intellectual development. While I find your strictly ontological argument from morality persuasive (regarding the existence of objective moral values and duties), I'm bewildered as to why you don't push the argument into epistemological territory. I am persuaded there is perhaps an equally powerful argument for the existence of God that should be offered, especially for the atheist convinced of moral realism, along the following lines: Assuming, as the atheist does, that it is unguided, our moral beliefs are accidents of the evolutionary process. For were there different environmental demands in the course of human evolution, very different moral beliefs would have evolved without the slightest change to our conviction that those beliefs were true. It seems this skeptical scenario is impossible to avert, short of an appeal to supernatural guidance of the evolutionary process with the goal in mind ensuring humans epistemological access to the correct set of morals.

In that case, doesn't this prove to the atheistic moral realist that God must exist, in the sense of a Creator and intelligent "guider" of our evolutionary development, as well as establishing His attribute of goodness in virtue of the fact that He took a special interest in assisting our moral ideation and formation? And if the atheist is not a realist about objective moral values and duties, couldn't this at least show he is incapable of logical consistency, as he thinks and lives with the assumption, unjustifiably, that we have a way of telling which of the infinite set of moral propositions are true, as opposed to merely being deceived by the skeptical scenario I described?

So, my question is twofold, really. Do you find this argument sound, and, if so, why do you not use it in your debates and popular work? Thank you so much for taking time to consider this!


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Dr. craig’s response


Rejoice and be glad, Jonah, because I have done exactly what you advise in my debate earlier this year with Erik Wielenberg on “God and Morality: What Is the Best Account of Objective Moral Values and Duties?” https://www.youtube.com/watch?v=6iVyVJAMiOY

Wielenberg is an atheistic moral realist who defends what he calls Godless Normative Realism. He treats, not only questions of moral ontology, but also questions of moral epistemology, devoting considerable effort to refuting so-called evolutionary debunking arguments against moral knowledge. So in my debate with him, I pressed objections both to his moral Platonism and to his moral epistemology. Taking my cue from a paper by Adam Johnson, it seemed to me that Wielenberg’s view is vulnerable to Alvin Plantinga’s celebrated Evolutionary Argument against Naturalism (EAAN). Plantinga argues that the person who believes in naturalistic evolution has a defeater for the reliability of his cognitive faculties in producing true beliefs and, hence, a defeater for his belief that naturalism is true. Since our moral beliefs are among the beliefs formed by our cognitive faculties, their reliability is also called into question by the naturalistic perspective, which Wielenberg accepts. Here is how I present the argument:


The third formidable objection I want to raise is that Dr. Wielenberg’s view seems to make moral knowledge impossible. Dr. Wielenberg’s account of moral knowledge seems vulnerable to Alvin Plantinga’s evolutionary argument against naturalism.[1] Plantinga argues that naturalism is self-defeating because if our cognitive faculties have evolved by naturalistic processes, they are aimed, not at truth, but at survival, and so cannot be relied on to produce true beliefs.  This is especially evident on Dr. Wielenberg’s view, since our mental states have absolutely no effect on our brain states.  Thus, the content of our beliefs is irrelevant to our survivability. But if we cannot rely on our cognitive faculties to produce true beliefs, then the belief in naturalism is itself undermined, since it has been produced by those very cognitive faculties.

We can apply Plantinga’s argument to our moral beliefs as follows:

1. The probability that our cognitive faculties are reliable, given naturalism and evolution, is low. 

2. If someone believes in naturalism and evolution and sees that, therefore, the probability of his cognitive faculties’ being reliable is low, then he has a defeater for the belief that his cognitive faculties are reliable. 

3.  If someone has a defeater for the belief that his cognitive faculties are reliable, then he has a defeater for any belief produced by his cognitive faculties (including his moral beliefs). 

4.  Therefore, if someone believes in naturalism and evolution and sees that, therefore, the probability of his cognitive faculties’ being reliable is low, then he has a defeater for the reliability of his moral beliefs.

Because our moral beliefs have been produced by faculties aimed at survival, not truth, we can have no confidence that our moral beliefs are true.

Dr. Wielenberg is acutely aware of this problem for Godless Normative Realism.  His very complex answer to this problem, simply put, is that the same cognitive processes that produce our moral beliefs also cause the abstract moral properties to be instantiated.[2]  Notice that this account depends crucially on the supposed causal connection between physical properties and abstract moral properties, which is perhaps the most obscure point in his philosophy.  But Plantinga’s argument gives us reason to doubt as well whether our cognitive processes which supposedly cause certain moral properties to be instantiated will trigger the appropriate moral beliefs, rather than beliefs which are merely conducive to survival.  Dr. Wielenberg reassures us that we are no more lucky in having true moral beliefs than we are in having true beliefs in general.[3]  But if Plantinga is right, it is an incredibly lucky coincidence, given naturalism, that our beliefs of any kind, including our moral beliefs, turn out to be reliable. 

The solution to this problem is to deny, not evolution, but naturalism.  On theism God can supervise the evolutionary process in such a way as to guarantee the fundamental reliability of our cognitive faculties.  Since Dr. Wielenberg, by contrast, is committed to naturalism as well as evolution, he has a defeater for the reliability of his moral beliefs.  Godless Normative Realism thus makes moral knowledge impossible.

I invite you to watch the debate and see how Dr. Wielenberg responds to this objection.

But in answer to your questions: (1) yes, the objection seems sound to me, and (2) I haven’t used the argument before, I suppose, because the EAAN is not an argument against the truth of naturalism (or for the truth of theism) but is an argument that naturalism cannot be rationally affirmed. It shows that even if true, naturalism cannot be rationally embraced.  By contrast the theistic argument related to moral ontology, if successful, shows theism to be true and naturalism false. So it fits better into my positive case for theism. But in this debate the EAAN served nicely as an objection to Wielenberg’s claim that Godless Normative Realism can guarantee us moral knowledge.

[1] Alvin Plantinga, Where the Conflict Really Lies:  Science, Religion, and Naturalism  (Oxford:  Oxford University Press, 2011), pp. 344-5.

[2] He claims that our moral beliefs are reliable when a particular non-conscious cognitive process classifies an entity as having certain non-moral properties and that classification triggers a conscious moral belief that the entity has a certain moral property and, moreover, a thing’s having the non-moral properties causes the thing to have that moral property (Erik J. Wielenberg,  Robust Ethics:  The Metaphysics and Epistemology of Godless Normative Realism [Oxford: Oxford University Press, 2014], p. 105).

[3] Ibid., pp. xii, 169, 172-3, 175.

- William Lane Craig