G.E. Moore and the Naturalistic Fallacy

Justifying Moral Values

Think about your most firmly held moral values. Now imagine that you have to justify them to the most inquisitive five-year-old conceivable.

If you believe, for example, that causing harm is wrong, why? Or if you think that maximizing happiness or pleasure is the right thing to do, what do you suppose makes it right? What makes fairness, respect, generosity, and truthfulness good? What does good (or bad or right or wrong) even mean?

You might see these questions as just the naïve ramblings of a moral novice, but can you answer them? Can they even be answered?

It’s hard to justify our moral values at the most basic level, and criticism of attempts to do so is not new.

In a previous post, I discussed David Hume’s view that what people ought morally to do can’t be inferred from factual, non-moral observations about the world. Hume’s view suggests that the foundations of our moral judgments rest on something other than logical deductions from non-moral states of affairs; for Hume, moral sentiments, rather than rationality, are what guide our moral judgments and actions.

The philosopher G.E. Moore, writing in the early 20th century, advances a similar – though not identical – criticism of the grounding of moral claims in non-moral observations, which Moore refers to as natural properties. In his book Principia Ethica, first published in 1903, Moore focuses on the nature of the fundamental moral concept good and how attempts to define it are confused. By good, Moore isn’t talking about whether anything in particular should be considered good but how the concept itself is to be defined.

The Naturalistic Fallacy and Defining Good

So, how should good be defined?

There is no shortage of possible definitions. Good is naturalness. Good is normalness. Good is virtuousness. Good is happiness. Good is pleasure. Good is fulfillment of duty.

Every single one of these is wrong, according to Moore, because good can’t be defined. And defining it in terms of natural properties, such as pleasure or happiness, is to commit what Moore calls the “naturalistic fallacy.”

It’s important to note that Moore isn’t saying that things that are pleasurable or natural or normal aren’t good or can’t be good. Many of them are good. He’s just saying that the property of goodness can’t be the same thing as pleasure, naturalness, normalness, or any other natural property, so any attempt to define it as such (e.g. “pleasure alone is good) is fallacious.

Trying to define good is like trying to define yellow. You can’t thoroughly explain it to anyone who doesn’t already know what it is. You can describe its physical equivalent, Moore says. “But a moment’s reflection is sufficient to shew that those light-vibrations are not themselves what we mean by yellow. They are not what we perceive …The most we are entitled to say of those vibrations is that they are what corresponds in space to the yellow which we actually perceive.”

Now think about the concept good. How do you explain it to someone who doesn’t already know what it means? You can’t, according to Moore because good, like yellow, is such a simple notion that it can’t be defined without referencing itself. Other things such as pleasure can contain the property good, but good can’t be reduced to pleasure or some other natural property. Good is simply good.

Moore contrasts good and yellow – simple concepts that can’t be broken down any further – with complex concepts, which can be. You can define a horse, for example, by listing its many different properties and qualities – it has four legs, hooved feet, and so on. But once you reduce it to its simplest terms, Moore says, those simple terms cannot be explained to anyone who doesn’t already know them. “They are simply something which you think of or perceive, and to any one who cannot think of or perceive or perceive them, you can never, by any definition, make their nature known.”

Like the simplest properties of a horse, good can’t be reduced to anything else, and trying to do so is a mistake. (Although Moore focuses on good, the basic idea – that moral properties can’t be reduced to natural properties – appears to apply to other moral properties, such as right, but Moore believed that the good was the ultimate end of ethical inquiry).

The Open Question Argument

To support his idea that good can’t merely be equated with natural properties, Moore proposes a thought experiment which has come to be known as the “open question argument”:

The hypothesis that disagreement about the meaning of good is disagreement with regard to the correct analysis of a given whole, may be most plainly seen to be incorrect by consideration of the fact that, whatever definition may be offered, it may always be asked, with significance, of the complex so defined, whether it is itself good.

For example, you may say that good means simply to promote the most overall happiness, and you may apply that definition to a particular question, such as whether it’s good to tax rich people at a much higher rate than poor people. And if you conclude that is indeed good, then you are thinking that it is one of those things that promotes the most overall happiness.

As plausible as your account may seem to you, the question “Is it good to promote the most overall happiness?” is still just as intelligible as the question “Is it good to tax rich people at a much higher rate?” It’s an open question. It can’t be settled in the same way that other definitional questions (e.g., “Is a bachelor married?) can. The notion that promoting the most overall happiness is alone what good means can always be doubted, “and the mere fact that we understand very well what is meant by doubting it, shews clearly that we have two different notions before our minds.”

Moore applies a similar line of reasoning to the idea that good is a meaningless concept that merely stands in for natural properties. For instance, if whatever is called good seems to always be pleasant, you might suppose that good and pleasant are the same thing. You might think that the statement “Pleasure is the good” isn’t referring to two distinct things, pleasure and goodness, but only to one – pleasure. Moore points out the flaw in this: “But whoever will attentively consider with himself what is actually before his mind when he asks the question ‘Is pleasure (or whatever it may be) after all good?’ can easily satisfy himself that he is not merely wondering whether pleasure is pleasant.”

Everyone, Moore says, understands that the question “Is this good?” can be distinguished from questions about whether things are pleasurable, or desired, or whatever else has been proposed as the definition of good. So, it only makes sense that good is a distinct concept and not merely one of these natural properties.

How to Deal with the Five-Year-Old

If Moore is right that our moral concepts are real but can’t be reduced to natural, empirically verifiable things in the world, then it would, in fact, be naïve of the probing five-year-old to expect that moral values can be explained in the same way that a horse can be explained to be a horse. But that doesn’t necessarily mean that our moral notions are baseless. Moore’s view is that our morality is intuitive and that moral truth is self-evident. So, when the five-year-old metaethicist asks why something is good, the answer is that it just is. And when he asks what makes it so, the answer is the property goodness. It might seem like these answers are dismissive, but remember Moore wrote a whole book working these same answers out.

Of course, some philosophers have given alternative interpretations of Moore’s thesis that morality can’t be demonstrated in natural terms. Rather than claiming that moral truths exist exist and are self-evident, like Moore does, these skeptics, called moral anti-realists, take the impossibility of inferring moral truths from non-moral truths as evidence that there is no objective morality. Try explaining this to a five-year-old: Morality is a sham!

If you want to give the kid what he’s likely asking for, you can try to justify your values according to readily available natural concepts. You can take the route of the moral naturalists and deny that the naturalistic fallacy is even a fallacy. You can embrace their view that moral truths exist and are natural facts just like anything else discoverable by science.

But first you have to get past Moore and Hume.