Ethical Theory Spring 2021

The Fact-Value Distinction


Hume and Moore, each in his own way, give statements of what is called the distinction between facts and values.

Facts are known by using the senses and factual beliefs can be true or false. By contrast, values cannot be known using the senses.

Can beliefs about values be true or false? Our authors split on this question.

Hume thinks that values are the products of what he calls our passions, that is, our desires. That makes them subjective in the sense that they come from us rather than the world.

Moore thinks that there are facts about values, but that they are non-natural facts. A natural fact is one that is known by the senses. This leaves him with a problem of explaining how we know about these facts.


I included two paragraphs from Hume. The first contains his statement that there are no facts about values, that is, in his terms, “moral distinctions.” The second denies the validity of drawing conclusions about what ought to be so from premises about what is, in fact, so. In other words, you can’t derive an “ought” from an “is.”

Here are some things to think about concerning Hume.

First, look at the numbered sentences in this paragraph.

Take any action allowed to be vicious; wilful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice. In whichever way you take it, you find only certain passions, motives, volitions, and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object. You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but it is the object of feeling, not of reason. It lies in yourself, not in the object. (1) So that when you pronounce any action or character to be vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it. (2) Vice and virtue, therefore, may be compared to sounds, colours, heat, and cold, which, according to modern philosophy, are not qualities in objects, but perceptions in the mind: and (3) this discovery in morals, like that other in physics, is to be regarded as a considerable advancement of the speculative sciences; though, like that too, it has little or no influence on practice. Nothing can be more real, or concern us more, than our own sentiments of pleasure and uneasiness; and if these be favourable to virtue, and unfavourable to vice, no more can be requisite to the regulation of our conduct and behaviour.

These are three themes that we will see asserted by philosophers who believe in the subjectivity of values.

  1. What you mean when you use a moral term is that you have a feeling.

  2. Moral beliefs are like beliefs about colors. Colors seem to be features of objects but are they are actually the products of our own minds.

  3. This discovery about the subjectivity of ethics has no practical impact; it won’t alter people’s behavior.

I think all three claims are open to question. The first is, on the face of it, false. The third seems questionable. The second, about color, is the most plausible.


Moore’s project is to define “good” in a way that would reveal its nature. Definitions that accomplish this, according to Moore, are ones that identify the component parts of the thing being defined in a way that enables you to distinguish it from other things. For example, if you know that a chimera is an animal with a lioness’s head and body, a goat’s head in the middle of its back, and a snake for a tail, you will know the nature of a chimera and you will be capable of distinguishing chimeras from other beasts (Moore 1903, 7).

Moore maintains that “good” cannot be defined in this way. It is simple, meaning that it does not have any parts. Since that is so, we obviously cannot explain what it is by identifying its parts.

Moore draws an analogy with color to explain what he means. All you can say about yellow is that it is the color that you see when you look at some things. It is different from other colors because it looks different. That, obviously, doesn’t enable anyone to identify yellow things or distinguish them from things that are not yellow. So it isn’t the kind of definition that Moore is looking for.

Moore thinks that hedonists get this wrong. They try to define “good” in terms of something else: pleasure. Their efforts fail, he maintains, because it is always an open question whether pleasure is good or not.

To see what he means, consider this definition: a bachelor is an unmarried man. You can ask whether the word “bachelor” means the same thing as “unmarried man.” But once you know what the words mean, you can’t really ask whether a given bachelor is an unmarried man or not. The answer is “yes” by the definition of the word.

Moore thinks that this argument extends to all attempts to identify “good” with a natural property or thing. That means that the same argument would apply to any attempt to define “good” in terms of things that we know through the senses.

Criticisms of Moore

Here are two questions about Moore’s argument that we can discuss.

First, how does he think we can distinguish between good and bad? If they aren’t identical with properties that we know through the senses, how do we know about them?

Second, is the so-called open question argument too broad? Take this definition: water is H2O. You can ask whether water really is H2O or not. Indeed, future scientists may discover that it is not! But that doesn’t make it a bad definition.


Hume, David. (1740) 1995. A Treatise of Human Nature. Edited by Mark C. Rooks. The Complete Works and Correspondence of David Hume. Charlottesville, VA: InteLex Corporation.
Moore, G. E. 1903. Principia Ethica. Cambridge: Cambridge University Press.