So as I understand, Moore's Open Question Argument can be formulated like this:


I. If x is the same thing as y, then the question "I know it's x, but is it y?" would be meaningless

II. The question "I know it's x, but is it good?" where x is some natural property is meaningful.

Therefore, good cannot be defined in terms of natural properties.


The thing I'm having trouble with is the second premise. If I said "I know he's a bachelor, but is he unmarried?" the question would seem to only reflect that I don't know what the heck the word "bachelor" means. But isn't he assuming that that isn't the case with the question "I know it's x, but is it good?"

In other words, couldn't it just be the case that, since it's possible that simply no one is properly informed on what "good" means, "x is good" could be a question of identity? Isn't he assuming it isn't, just because the two terms "feel" different?

For example. Let's say that no one on Earth knew what "bachelor" meant. So if someone asked "I know he's a bachelor, but is he unmarried?" that would seem like a genuinely meaningful question. In the same way, couldn't it be the case that "x is good" where x is some natural property, for example "'pleasurable' is 'good'", is genuinely a question of identity, it's just no one knows the true nature of good, so it feels like a meaningful question to ask?

Sorry if this isn't too lucid of a question.

  • 1
    If no one is properly informed on what "good" means then the word is gibberish and there is no point to asking questions about it, whether it is definable in terms of natural properties or any other. Since it makes the whole discussion moot this possibility can be safely disregarded. A bigger problem is with premise I, as questions like "does Lois Lane know that Clark Kent can fly?" show. Clark Kent is the same thing as Superman, but the answer changes when the latter is substituted into the question.
    – Conifold
    Sep 13, 2022 at 23:07
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    The argument as you present it is equivocating on the meaning of "is". In the first premise, "is" means "is identical to". In the second premise, "is" means "has the property". Sep 14, 2022 at 0:48
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    Indeed as moral philosopher William Frankena first raised above 2nd premise as beg the question: He assumes that the question is a meaningful one. This begs the question and the open-question argument thus fails... the open-question argument can be reformulated. The Darwall-Gibbard-Railton reformulation argues for the impossibility of equating a moral property with a non-moral one using the internalist theory of motivation. Goodness, on this account, is the property...not, itself, equivalent to those states... Sep 14, 2022 at 3:17
  • See Moral Non-Naturalism: One can allow that goodness is itself a non-natural property but grant that all pleasant things necessarily have that non-natural property. What the non-naturalist must reject is the thesis that such suppressed premises are true in virtue of the identity of goodness with the natural property in question. So the so-called naturalistic fallacy is no fallacy at all. Rather, if Moore is right then the so-called naturalistic fallacy actually embodies a mistaken belief about the reducibility of goodness Feb 12 at 16:00

3 Answers 3


I'm going to (tentatively!) concur by offering a variation on the theme of your argument. So Moore seems to have used "good" very rigidly, but I think a lot of people mean all sorts of different, but similar, things by otherwise equivalent question-tokens. So here,

  1. Is pleasure good?
  2. Is the concept of goodness definable from the concept of pleasure?
  3. Is this pleasure-promoting thing good? (In reference to a given situation, not to general issues concerning the nature of goodness.)
  4. Is this pleasure-promoting thing right?

... are some of the salient options. (1) could be legitimate in the sense that we don't know the surface meaning of every or even our simpler terms, and so we might "forget" or be "distracted from" the fact that talking about something being good means portraying it in a favorable light, a state of affairs that cannot help be caught up in emotional and hence conative representations, and thus with "desirable pleasure." (2) could be a reframe of (1) or, rather, a way to accept the gist of (1) without adverting to full-on reductionism. (3) gets at the more specific kind of divergent use of "good," in that what might be closable for, "Is pleasure good?" is kept open for, "Is this pleasurable thing good?" And then (4) implements (3)'s theme further, cashing out the divergent sense of "good" in terms of the higher-order mystery of interdefining rightness and goodness (and/or other terms entirely), a mystery to which Moore did try to offer a solution, but which he doesn't appear to have consistently framed, and which didn't work out otherwise anyway (i.e. his generic aggregationism about "ought," except that he also defined goodness as that which "ought to exist for its own sake"!).


An interesting question. Demonstrates the equivalence between ignorance (epistemology) and impossible (metaphysics). How can you tell there is no evidence and there is evidence, I haven't found it yet? Is it that it is impossible to define good with natural properties or is it that it's possible to define good with natural properties but we're ignorant as to how?


Yes, it does beg the question, in that it assumes that a question of the form "I know it's x, but is it good?" is always meaningful, which is in effect assuming that good can never be shown to be analytically equivalent to some property x. In other words, he was implicitly assuming what he was trying to prove.

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