Excursus on Natural Theology (Part 18): The Moral Argument

February 03, 2016

Moral Argument

In our excursus in natural theology, we’ve talked about the proper basicality of belief in God, we have looked at the cosmological argument from contingency, we have examined the kalam cosmological argument, and most recently completed a study of the teleological argument based on the fine-tuning of the universe for a cosmic Designer. Today we want to turn our attention to a new argument which is the moral argument for God’s existence.

We can begin thinking about this by asking ourselves a question: Can we be good without God?

At first blush the answer to this question might seem so obvious that even to pose it is apt to make people angry. For while we Christians find in God a source of moral strength that enables us to lead better lives than we should have without him, nevertheless it would be arrogant and ignorant to claim that nonbelievers do not often lead good moral lives—in fact, lives that sometimes put our own lives to shame if we are honest.

But wait a minute! It would, indeed, be arrogant and ignorant to claim that people cannot be good without believing in God. But that wasn’t the question. The question was: Can we be good without God? When we ask that question, we’re posing in a provocative way a question about the nature of moral values. Are the moral values that we hold dear and guide our lives by just social conventions, like driving on the right-hand versus the left-hand side of the road? Or are they merely expressions of personal preference, like having a taste for vanilla instead of chocolate? Or are they somehow binding and valid independent of our opinion, and if they are then what is their foundation?

Many philosophers have thought that morality provides a good argument for the existence of God. I myself stumbled into the moral argument, so to speak, through the back door. I was speaking on university campuses on the absurdity of life without God. I argued that if there is no God then ultimately life is purposeless, meaningless, and valueless, in particular there is no foundation for objective moral values. Everything becomes relative. To my surprise, the response of students to this claim was often to insist that objective moral values do exist. We know that certain things are right and wrong, and therefore certain moral values really do objectively exist. What the students said didn’t in any way refute my claim that without God there would be no objective moral values. Instead, what they had done was to unwittingly provide a missing premise in a moral argument for God’s existence.

We can now argue:

1. If God does not exist, objective moral values and duties do not exist.
2. Objective moral values and duties do exist.
3. Therefore, God exists.

This simple little argument is logically ironclad. If the two premises are true then the conclusion follows necessarily and logically. Moreover, this argument is very easy to memorize and share with another person. I had argued for the truth of the first premise; the students had insisted on the truth of the second premise. Together the two premises logically imply the existence of God.[1]

I think what makes this argument so powerful is that people generally believe both premises. In a pluralistic age – a relativistic age – students are scared to death of imposing their values on someone else. The conventional wisdom is that you can’t tell somebody else that they are wrong and you are right. Who are you to judge someone else in that way? So premise (1) seems correct to them. At the same time, certain values have been deeply (indeed I think unconsciously) instilled into them, such as tolerance, open-mindedness, and love. In particular, they think that it is objectively wrong to impose your values on someone else! So they’re deeply committed to premise (2) as well. They’ve just never put the two together to see what the implication is.

This can lead to some very strange conversations. I remember talking once with a nonbeliever who would jump back and forth between the two premises. When we’d talk about the first premise, he’d agree with it but deny the second premise. But then when we’d move on to the second premise, he’d agree with it and deny the first premise! So back and forth we went with him unable to make up his mind which one he believed and which one he rejected. It would have been funny had it not been so pitiful to see someone floundering in this way simply out of a vain attempt to avoid God.

So what I’d like to do is examine more closely each of the argument’s two premises in order to see what defense you can offer on their behalf and also what objections the nonbeliever might raise against them.

Let’s take a look first at premise (1), that if God does not exist objective moral values and duties do not exist.

Before we can say something in defense of this premise, I want to clarify a couple of important distinctions. First, notice that I distinguish between values and duties. Values have to do with whether something is good or bad. Duties have to do with whether something is right or wrong. Now you might think that this is a distinction without a difference. You might think that “good” and “right” mean the same thing, and the same goes for “bad” and “wrong.” But if you reflect on it for a moment, I think you will see that this isn’t the case.

Duty has to do with moral obligation, what you ought or ought not to do. But obviously you’re not morally obligated to do something just because it would be good for you to do it. For example, it would be good for you to become a doctor, but you’re not morally obligated to become a doctor. After all, it would also be good for you to become a firefighter or a farmer or a homemaker, but you can’t do all of them. So it is simply not true that because something is good to do that it means you have a duty or moral obligation to do it. Furthermore, sometimes all we have is bad choices. Think, for example, of the movie Sophie’s Choice where the poor mother has to choose which of her two children are to be sent by the Nazi soldiers to the concentration camp. No matter what she chose, it is a bad state of affairs. Yet it is not wrong for her to make a choice because she must choose in that circumstance.[2]

So there’s a difference between what is good and bad and what is right and wrong. Good and bad has to do with something’s moral worth, and right and wrong has to do with something’s being obligatory.

There is a second distinction that I want to clarify, and that is the distinction between something’s being objective versus subjective. By “objective” I mean “independent of people’s opinions.” By “subjective” I mean “dependent upon people’s opinions.” So to say that there are objective moral values is to say that something is good or bad independent of what people think about it. Similarly, to say that we have objective moral duties is to say that certain actions are right or wrong for us regardless of what people think about it.

So, for example, to say that the Holocaust was objectively wrong is to say that it was wrong even though the Nazis who carried it out thought that it was right, and it would still have been wrong even if the Nazis had won World War II and succeeded in brainwashing or exterminating everybody who disagreed with them, so that everyone agreed that the Holocaust was right. Premise (1) claims that if there is no God then moral values and duties are not objective in that sense.


Student: I’ve heard some people ask why you define “objective” as independent of persons or human opinion. They will say usually “objective” is defined as mind-independent. But, of course, if it is mind-independent then it can’t be rooted in God at that point.

Dr. Craig: I think the reason is that when people say mind-independent (I can virtually guarantee this) they are thinking about people. They are not thinking of God when they say, for example, that abstract objects are a mind-independent reality as a Platonist claims. They are not thinking about God. They are thinking about it being independent of human opinion. The reason that that is justified, I think, is if you say that mind-dependent excludes being dependent on God then everything becomes mind-dependent. The distinction becomes trivial; it becomes meaningless. Because then even the existence of the external world is mind-dependent because it wouldn’t exist if God didn’t exist. The intuitively meaningful distinction between mind-dependent and mind-independent collapses if you say that it should encompass God as well.


You might notice that I don’t use the words “absolute” versus “relative.” “Absolute” would mean independent of the circumstances in which one finds oneself, whereas “relative” would mean that what is right or wrong or what is good or bad would be relative to the circumstances. I am not claiming that there are absolute moral values as opposed to values that are merely relative. Rather, in whatever circumstances one finds oneself, there will be a right thing to do and a wrong thing to do. But one isn’t claiming that these are not relative to the circumstances. In some circumstances it will be justified, for example, to take a human life – if there is a terrorist about to commit a suicide bombing. In other circumstances it would not be justified to take a human life – if it is an innocent person, for example. So we are not making a claim here about absolute versus relative. Don’t confuse that distinction with the distinction of objective versus subjective.


Student: Could you tell us about existence? Because I don’t think we have to commit ourselves to be Platonists to keep everything real and say these things exist and therefore they are beings in your ontology.

Dr. Craig: The word “exists” or “existence” in ordinary English has a very light sense. It is that sense in which I am speaking here.[3] You could rephrase it to say something like this, “if God does not exist then there are no objective moral values and duties,” and take again “there are” to be a light sense in the sense in which I say, “There are five Fridays in October.” Nobody who thinks that is true thinks that there are objects or things called “Fridays” which are mind-independent objects in the world. Right? I am using the word in a light sense here, not in a heavy sense that would commit us to Platonic abstract objects.

You could avoid the language of existence or being all together by just saying, “if God does not exist, moral values and duties are not objective.” That will be a restatement of what I want to say. The second premise would be restated, “Moral values and duties are objective.” Therefore, God exists. Then you can just avoid any misunderstanding about positing Platonic abstract objects which are virtues or vices. We will come back to this again later on as an alternative to theism actually.


Let’s move to a defense of premise (1). Let’s begin by considering, first, moral values. Traditionally moral values have been based in God, who is taken to be the highest Good. But if God does not exist then what is the basis of moral values? In particular, why think that human beings have objective moral worth? The most popular form of atheism is naturalism. Naturalism holds that the only things that exist are the things that are postulated by our best scientific theories. But science is morally neutral; you can’t find moral values in a test tube. So it would follow immediately that moral values and duties don’t exist on naturalism; they’re just illusions of human beings.

Even if the atheist is willing to go beyond the bounds of science, why should we think that on atheism human beings are morally valuable? After all, in the absence of God, they are just accidental byproducts of nature which have evolved relatively recently on an infinitesimal speck of dust called the planet Earth lost somewhere in a hostile and mindless universe and which are doomed to perish individually and collectively in a relatively short time. Richard Dawkins’ assessment of human worth may be depressing, but why on atheism is he wrong when he says, “there is at bottom no design, no purpose, no evil, no good, nothing but pointless indifference. . . . We are machines for propagating DNA. . . . It is every living object’s sole reason for being.”[4]

On an atheistic view, moral values seem to be just the byproduct of biological evolution and social conditioning. Just as a troupe of baboons exhibit cooperative and even self-sacrificial behavior because natural selection has determined it to be advantageous in the struggle for survival, so their primate cousins Homo sapiens have similarly evolved this type of behavior for the same reason. As a result of socio-biological pressures there has evolved among Homo sapiens a sort of “herd morality” which functions well in the perpetuation of our species. But on the atheistic view there doesn’t seem to be anything about Homo sapiens that would make this morality objectively true. Charles Darwin himself wrote in his book, The Descent of Man,

If . . . men were reared under precisely the same conditions as hive-bees, there can hardly be a doubt that our unmarried females would, like the worker-bees, think it a sacred duty to kill their brothers, and mothers would strive to kill their fertile daughters, and no one would think of interfering.[5]

To think that human beings are special is to succumb to the temptation to species-ism, that is to say, an unjustified bias in favor of one’s own species.[6]

So if there is no God, any basis for regarding the herd morality evolved by Homo sapiens on this planet as objectively true seems to have been removed. Take God out of the picture, and all you’re left with is an ape-like creature on a speck of solar dust beset with delusions of moral grandeur.

Second, now consider moral duties. Traditionally our moral duties were thought to spring from God’s commandments, such as the Ten Commandments. But if there is no God then what basis remains for objective moral duties? On the atheistic view, human beings are just animals, and animals have no moral obligations to one another. When a lion kills a zebra, it kills the zebra, but it does not murder the zebra. When a great white shark forcibly copulates with a female, it forcibly copulates with her but it does not rape her because there is no moral dimension to these actions. They are neither prohibited nor obligatory.

So if God does not exist, why think that we have any moral obligations to do anything? Who or what imposes these moral obligations upon us? Where do they come from? It’s hard to see why they would be anything more than just a subjective impression arising from societal and parental conditioning.

Certain actions like incest and rape may not be advantageous biologically and socially and so in the course of human development they have become taboo. But that does absolutely nothing to show that rape or incest is really wrong. Such behavior goes on all the time in the animal kingdom. The rapist who goes against the herd morality is doing nothing more serious than acting unfashionably, the moral equivalent, as it were, of Lady Gaga. If there is no moral lawgiver then there is no objective moral law which we must obey.

Now it’s extremely important that we clearly understand the issue before us. I can almost guarantee that if you share this argument with an unbeliever, someone is going to say indignantly, “Are you saying that atheists are bad people?” They will think that you are judgmental and intolerant. We need to help them see that this is a complete misunderstanding of the argument.

The question is not: Must we believe in God in order to live moral lives? There’s no reason to think that nonbelievers cannot live what we would normally characterize as good and decent lives.

Again, the question is not: Can we recognize objective moral values and duties without believing in God? Again, there’s no reason to think that you have to believe in God in order to recognize that, for example, you ought to love your children.

Or again, the question is not: Can we formulate a system of ethics without referring to God? If the atheist recognizes and affirms the intrinsic value of human beings, there’s no reason to think that he can’t work out an secular system of ethics or code of conduct that the believer will largely agree with.

Rather the question is: If God does not exist, do objective moral values and duties exist? The question is not about the necessity of believing in God for objective morality; the question is about the necessity of God for objective morality.

I’ve been shocked at how often even professional philosophers, who ought to know better, confuse these two questions.[7] For example, I participated in a debate at Franklin and Marshall College in Pennsylvania with the late humanist philosopher Paul Kurtz on the topic “Goodness without God is Good Enough.”[8] I argued that if God does not exist then there are no objective moral values, duties, or accountability for one’s actions.

Kurtz, to my astonishment, completely missed the point. He replied,

If God is essential, then how is it possible for the millions and millions of people who don’t believe in God to nonetheless behave morally and ethically? On your view, they could not. And so, God just is not essential. . . . many people, indeed millions of people, have been optimistic about life, have lived a full life, and find life exciting and significant. Yet, they don’t wring their hands about whether or not there is an afterlife. It’s living life here and now that counts.

Kurtz’s point only shows that belief in God is not necessary to living a moral, optimistic life. It does nothing to refute the claim that if there is no God, then morality is just a human illusion.

To repeat: belief in God is not necessary for objective morality; God is.


Student: I have a lot of inner turmoil over this particular discussion. I don’t see the conclusion as proved that God is required for that. I think that there is a leap there that is unsupported.

Dr. Craig: All right. Can you explain why? How would you respond to what I said that if God does not exist then you’ve lost any objective basis for moral values and you’ve lost the source for moral obligation. Where on the atheistic or naturalistic view will moral values and duties be grounded?

Student: From my personal experience . . . I will speak from my relationship with my father because my father would call himself a naturalist – he does not believe in God. He lives in an objective moral framework that is about his respect for however this world happened it is good and should be preserved and protected. However society got to where we are today it should be preserved and protected. But what you are saying is whether he knows it or not, his beliefs stem from the fact that God exists?

Dr. Craig: No, is that what I am saying? Am I saying that whether he knows it or not that his belief that society should be protected and preserved stems from God? Have I made that claim? I’m not asking you, I’m asking the class. No, I haven’t made that claim. What I’ve said is that he is right that objective morality exists and that society ought to be preserved and protected. He is right. That is premise (2)! What I am challenging is, I want to know from his point of view (if atheism is true) why ought society to be preserved and protected? Why think that that is an objective duty that human beings have to preserve this society on this planet?

Student: Pain aversion, I suppose.

Dr. Craig: Now that is a common answer, but then I want to know why should we avoid inflicting pain on other persons in our species? Animals inflict pain upon one another all the time. So why are we different? Why is it wrong for Homo sapiens – this relatively advanced primate – to inflict pain?

Student: OK, I am stunned. From the perspective of my father – I am here because I kind of see both sides. I think I see both sides. I don’t have black and white certainty in either direction.

Dr. Craig: OK, don’t let certainty become a sort of bugaboo here. All that is required for a successful argument is that the premises be more plausible than their opposites. Even if it is, say, 52 to 48 percent you should go with what seems more probably true. I am not arguing here about certainty. Just that I think the premise is true that if there is no God then moral values and duties aren’t objective.[9]

Student: Here is really my question. It is all very confusing, and like I said it is turmoil and I probably shouldn’t have spoken first, but . . .

Dr. Craig: On the contrary, you should!

Student: My question then, or what I have been feeling is, are you leading up to a judgment that objective morals are superior to subjective morals? Because then I could say that maybe my dad lives in subjective morality, right? If that is different. Because he has decided not to hurt people because for whatever reason subjectively.

Dr. Craig: I think you are construing this again exactly the way I said we should not construe it – that atheists are bad people. That is not the argument. It is not a judgment about your father, or his moral life or virtue. The conclusion to which I am leading is that God exists. That is the conclusion.

Student: That is not obvious to me based on the fact that objective morality . . . for me there is something missing between the behavioral reality of . . . I see it with my friends raising children. When “Wait until your father comes home” isn’t scary enough that you have to say “Don’t let God see that!” “Don’t let God see you doing that.” I understand that. From my father’s perspective, and kind of from my perspective too, I want to say almost the question of God is a little bit irrelevant because I am going to behave in a good fashion as I see it. Even if it turns out that there was no God, I am not disappointed in myself. I am still proud of myself for behaving as though there is one.

Dr. Craig: I think, again, that you are misunderstanding the argument. There you are asking about the question of moral motivation. Should I be good because, say, God will reward this if I do, and if I don’t he’ll punish me. You are asking about, “What is the source of our motivation for the moral life?” I am not even addressing that question. I tend to agree with you that you do the good for the good’s sake. You do it because it is good.

Student: I would consider that under duty.

Dr. Craig: What we are asking about: is there a basis or an explanation for why something is good rather than bad, and why we have an obligation to do certain things and an obligation not to do other things. Where do those obligations come from? Are they just fobbed off onto us by the evolutionary process and societal conditioning or are there objective values and duties that are valid and binding independent of our apprehension of them. That is the question.


We come to the end of our time. I don’t want to go beyond that. But next time we will continue our discussion and we will look at some more objections to premise (1) and perhaps this will help to strengthen the case for premise (1) by showing how the objections that are usually lodged against it I think ultimately are unsuccessful.[10]



[1] 5:11

[2] 10:00

[3] 15:00

[4] Cited in Lewis Wolpert, Six Impossible Things before Breakfast: The Evolutionary Origins of Belief (New York: Norton, 2006), 215. Unfortunately, Wolpert’s reference is mistaken. The quotation seems to be a pastiche from Richard Dawkins, River out of Eden: A Darwinian View of Life (New York: Basic, 1996), 133, and Richard Dawkins, “The Ultraviolet Garden,” Lecture 4 of 7 Royal Institution Christmas Lectures (1992), http://physicshead.blogspot.com/2007/01/richard-dawkins-lecture-4-ultraviolet.html. (Thanks to my assistant Joe Gorra for tracking down this reference.)

[5] Charles Darwin, The Descent of Man and Selection in Relation to Sex, 2nd edition (New York: D. Appleton & Company, 1909), p. 100.

[6] 20:14

[7] 25:05

[8] A full transcript of this October 2001 debate, along with essays from several people on both sides of the issue, can be found in Is Goodness without God Good Enough?: A Debate on Faith, Secularism, and Ethics (Rowman & Littlefield, 2008).

[9] 30:10

[10] Total Running Time: 34:04 (Copyright © 2016 William Lane Craig)