The Moral argument

This page last updated June 24th, 2016

Human societies can only function by agreeing on laws and ethics, and most of the basic ethical beliefs around the world are similar. The moral argument asks where these beliefs came from, are they really true, and does it require God to make it so? We will consider two slightly different formulations of the argument.

Some clarifications

Epistemology and ontology

We might as well start with some big words. Ontology refers to what actually exists, how things are, whether we know them or not. Epistemology refers to how we know things, or believe things. We will look at two versions of the moral argument, one based on each concept.

Values and duties

In discussing this argument, philosopher William Lane Craig makes this distinction. Moral values are about what is good and bad; moral duties about actions which are right or wrong.

Objective and subjective

Objective means true regardless of whether anyone believes it or not; subjective means that each person can reasonably make up their own minds. So the statement The temperature today is 12 degrees is objectively true or false because it can be verified regardless of what I feel, whereas I feel cold is subjectively true, because you may not.

In the case of ethics, objective ethics means true regardless of what different people or cultures may think, whereas subjective ethics means that each person or culture may legitimately decide for themselves.

Let’s avoid some misunderstandings

In looking at the basis of ethics, there are some things we are not saying.

  • There is no inference that only theists can behave ethically.
  • We are not suggesting that only theists can formulate a system of ethics.
  • We are not saying that only theists can believe in objective ethics.

In all cases, atheists may believe or act the same as theists. The question is what is the logical basis for this behaviour.

The moral argument

The argument

  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.


The argument is logically valid, so we need to look at the justification of the two premises.

Premise 1 is justified by considering the situation if there is no God. Then humans would the products of evolution, just as animals are, and there would be no qualitative difference between the two. Natural selection would reinforce behaviour that leads to personal or group survival.

This premise is accepted my many atheists, but certainly not all. In effect supporting the premise, Richard Dawkins said: There is at bottom no design, no purpose, no evil, no good, nothing but pointless indifference …. Professor William Provine said: Naturalistic evolution has clear consequences …. no ultimate foundation for ethics exists…. And philosopher Michael Ruse has said:

Considered as a rationally justified set of claims about an objective something, ethics is illusory. I appreciate when someone says “Love thy neighbour as thyself” they think they are referring above and beyond themselves….. [But] such reference is truly without foundation. Morality is just an aid to survival and reproduction …. and any deeper meaning is illusory.

Some atheists are uncomfortable with this premise – their views are considered below under “objections”.

Premise 2 can be justified by observing human behaviour.

It is a fact that most people instinctively feel some behaviours are admirable and right (e.g. helping someone who is suffering, even if a stranger), while others are repulsive and wrong (e.g. pedophilia, genocide, rape). If we suggested that this was just their personal idea, and other views on the matter were equally legitimate (i.e. these views are subjective), most people would disagree, quite strongly.

Philosopher Bertrand Russell, whose philosophy led him to believe in subjective ethics, nevertheless said in commenting on the Nazi atrocities in World War 2:

I do not myself think very well of what I have said on ethics. I have suffered a violent conflict between what I felt and what I found myself compelled to believe …. I could not bring myself to think that Auschwitz was wicked only because Hitler was defeated ….

This constitutes a strong argument that most people believe our ethical judgments are based on objective standards. Our moral duties are based on objective moral values.

The concept of human rights also supports the idea that ethics are objective. Most people believe human rights are a given, not just something we have invented. We would have no basis for developing a charter of human rights, and holding international war crimes trials, unless we were imposing a set of moral values and duties that we regarded as universal.

The conclusion (3) therefore seems to be reasonable.


The most common objection against Premise 1 is known as Euthyphro’s Dilemma, which was first formulated by Plato. It consists of a simple question to those supporting this premise: Is a moral value true because God commands it, or does God command it because it is true?

Because God commands it ….

Many theists answer that something is right because God commands it. This certainly makes objective moral values and duties dependent on the existence of God, but at a cost. For this would make it equally likely that God could forbid rape or command it – because there is no external moral command by which we can judge God’s actions.

Theists try to get around this problem by arguing that God’s commands, which lead to our moral duties, arise from his character which defines moral values. Thus our moral duties do indeed depend on God, yet there is no external moral code which God himself is subject to.

I have not been able to convince myself that this sidestep is valid. If we say God’s nature is good, then we have a moral value by which we measure God’s goodness. But if we say God’s nature defines good, then we are left with the problem of whether that nature is arbitrary.

Because it is true ….

But if we then answer that God commands those things that are good, then we are saying that there are moral values independent of God. I don’t find this a problem myself (after all, it would appear that the rules of logic and mathematics would be true even if there was no God), but it does undermine the first premise of the moral argument.

But where do ethics come from?

The Euthyphro Dilemma is essentially a negative argument, and leaves unanswered where objective ethics come from or how they reside. Some atheists (as already noted) think there can be no objective ethics, but others have attempted to find a way.

For example, David Brink argues that we can take our strong moral convictions about some matters as a sign of the objectivity of moral values, although his suggestion of how they may have come to be objective are not so convincing. Others say our feelings of revulsion or admiration are indicators of objective moral values, but again, no satisfactory explanation is given of how such feelings can be considered to be objective.

Many other atheists object to Premise 2, arguing simply that ethics are pragmatic – they work and they are necessary for our societies and species to survive – and so we have evolved to feel this way. If asked how they can therefore make a judgment against a society or individual that evolved or chose differently (e.g. Nazi Germany), they struggle to find an answer that reflects how they undoubtedly feel about events like the Holocaust. Nevertheless, the view can be maintained.


This version of the moral argument appears to be effective for people who feel strongly about the reality of ethical values and want to understand why they are so universal. But both premises are problematic and can be argued against, even though those arguing this way struggle to find any alternative basis for their moral feelings.

A moral knowledge argument

The argument

  1. If God does not exist, we cannot know moral values and duties are objective and true.
  2. We do know moral values and duties are objective and true.
  3. Therefore God exists.


We can support Premise 1 by noting that humans have no faculty or procedure for verifying moral values and duties. We can verify mathematical statements by logical proofs or doing the calculation over again, and we can verify scientific conclusions by repeating the observation or experiment. But there is no known means of “proving” moral values are true.

However if God reveals a truth about moral values, then we can believe on his authority that it is so.

The same arguments as noted above can be used for Premise 2 in this argument – human behaviour shows that we feel we can know certain things are right and wrong, good and bad.


This version of the argument avoids Euthyphro’s dilemma, but the atheist can still argue against both premises.

As before, the atheist can argue that Premise 2 is false, and that all ethics are subjective. Or, alternatively, the opponent argue against Premise 1 by pointing out that, with so many different religions, there is no clear way to know which ethic we can know to be ‘right’.


It seems to me that this version of the argument is actually stronger than the previous one, because it avoids Euthyphro’s Dilemma. However it doesn’t seem to have been used much, and is therefore untested, and the opponent can still claim ethics are subjective.


The moral argument can therefore be considered a slight positive for theism, because theism supplies more of an explanation (albeit not entirely satisfactory) of the origin of objective moral values and duties, and of our knowledge of them, than does atheism. A person who believes our moral values and duties are important and objective is likely to be impressed by this argument, but there are sufficient doubts to make it less convincing for others.

However avoiding either version of the argument by denying that ethics are objective leads to unattractive, and perhaps unlivable, conclusions, that our instinctive and shared moral values cannot be taken as ‘true’, and so any condemnation of those who flout common ethical standards is subjective only.

The Stanford Encyclopedia of Philosophy sums up:

Moral considerations give all a reason to examine the proposition that there is a God very seriously. For if there is no God, morality is a more perilous enterprise than if there is.

Photo: MorgueFile. Page last updated: 12 March 2016.

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