Let us use the original argument:

  • Premise 1: If X is good, then the question "Is it true that X is good?" is meaningless.
  • Premise 2: The question "Is it true that X is good?" is not meaningless.
  • Conclusion: X is not good.

Now we put the oppossite:

  • Premise 1: If X is not good, then the question "Is it true that X is not good?" is meaningless.
  • Premise 2: The question "Is it true that X is not good?" is not meaningless.
  • Conclusion: X is good.

It can't be true that X is good and not good at the same time. This means something is wrong with premises.

Wikipedia states that Moore begs for question in second premise. But I don't see anything wrong with second premise. We can replace goodness of X by any other statement and thus say any question is meaningless. But actually, it's unintuitive to think that no question is meaningful.

Therefore it's in the first statement - "If X is Y, then the question "Is true that X is Y" is meaningless." What exactly is wrong in such a proposition?

  • I cannot understand... The two arguments are valid but in order to assert that the conclusion is TRUE we must have TRUE premises. What about premise 1 : If X is good, then the question "Is it true that X is good?" is meaningless. What does it mean ? How we can say that it is TRUE ? May 15 '18 at 15:46
  • @MauroALLEGRANZA, that's Moore's argument. And that is what I am asking: is premise 1 wrong? And then does not it produce another argument: nothing really can be good or not good?
    – rus9384
    May 15 '18 at 15:50
  • @MauroALLEGRANZA, yes, argument itself is valid (modus tollens) but if result is invalid, then at least one of the premises is invalid. What does it mean if question is meaningless I don't know. But I think this should be answered from epistemological position, since premises involve such notions as "meaning" and "true".
    – rus9384
    May 15 '18 at 15:59
  • You are confusing premise content & logical form. Don't worry about content now. The form of the argument is a Modus Tollens. In each case in this form you negate the antecedent which is done in BOTH cases. You then think about the content which is an error. The second premise does not even mention the act of X. Only the first premise does. The second premise only negates the consequent. The content evaluation of the argument would be a different process. This would involve soundness of the argument which requires true premises and validity in the argument at the same time.
    – Logikal
    May 15 '18 at 17:13
  • @Logikal, I understand that it's imposible that two premises both are correct. But actually, if I find the question "Is it true that X is Y" not meaningless one. Indeed, "Is it true that blackholes exist?" is not a meaningless question. Therefore, something is wrong in the first premise. If we replace "X is [not] good" with "blackholes [do not] exist" we get some epistemological problem.
    – rus9384
    May 15 '18 at 17:38

It seems I came to the solution:

But what is the epistemological reason for our mind? What is it's purpose in this context? The reason is clear: to acknowledge something that is unknown, to understand something that is not understood. Therefore the question appears: what is understood and what isn't?

Here are two cups. One on my right hand and one on my other hand. One is red and one is black. One is filled with pure water and the another with sugar water. Some of you are blindfolded, and you don't know what color the cup on my right hand is. It's an open question for you. Others, who are not blindfolded, know what color it is. It is not a meaningful question for them. But no one of you know what water is poured into that cup. Only I know.

But does that mean the question has multiple truths? Clearly no. From your intuitive view it is possible that red cup is filled with clear water and it is possible that it is filled with sugar water. But your intuition is all about the theory and not facts. Yes, any cup can contain any water and be placed on either hand of mine. But the fact can be only one: the red cup contains sugar water.

So, the reason why question is meaningless is not because it has a positive answer, but because the answer is unknown, either it is positive or negative. This is a mistake made by Moore in his first premise. And open question argument disproval.

  • +1, Hi : Moore doesn't say that the question is 'meaningless' - does he even use the word in PE ? He says it is 'unintelligible', which is hardly crystal-clear but indicates to my mind that the question would be quizzical and pointless, like asking if a square is a rectangle. If X = Y, there would be the same unintelligibility but there isn't, so X ≠ Y. For the reasons I gave, I think this is a poor argument ontologically and epistemologically. I agree with you that epistemology, lack of knowledge, does not settle the question of identity and your examples bring this out well. Best - Geoff.
    – Geoffrey Thomas
    May 16 '18 at 4:34

The question is if something is in a state it is meaningless to ask if it is in that state.

But this is a premise not a linked truth. Something could fluctuate between states, and either state be undetectable. In this case it is not meaningless to ask is it in one state or the other though it maybe impossible to find the answer even if it is only in one state. If the state is static and detectable, asking the question to something you already know the answer to serves no point.

So asking a totally open question without constraints means it may make sense and be true and also it may be false and be wrong.

The second premise, excludes cases where you know the state of the object, which is mutually exclusive to the first premise. So both premises cannot exist together.


I always thought the Open Question Argument, whatever its merits, depended on the identity of properties.

If we identify some natural or metaphysical property, such as promoting the survival of the species or producing pleasure or pleasing God (X) with the moral property of goodness (Y), so that they are one and the same (X = Y), then it would not be intelligible to ask : 'Ψ is X but is it Y ?' But it is intelligible to ask this, therefore X (for any X) is not identical with Y. That is the central thrust of Moore's argument.

This strikes me as a weak argument. Ontologically the possibility of the question proves nothing : e.g. if the Morning Star = the Evening Star then they are in fact identical and the question : 'That's the Morning Star but is it the Evening Star ?' has only one correct answer : 'Necessarily, yes'. The possibility of the question does not defeat the fact of identity. There is a question but no Open Question. Moore has not proved that ontological identity does not hold between X and Y. So by parity of reasoning, 'It produces pleasure but is it good ?' also only has one answer (if this particular identity holds) : 'Necessarily, yes'. There is a question but Moore has not proved that it is an Open Question.

Epistemologically the Open Question Argument is broken-backed. It is perfectly intelligible for someone who does not know that the Morning Star is the Evening Star to ask : 'That's the Morning Star but is it the Evening Star ?' And the correct response is 'Yes'. The intelligibility of the question does not defeat identity in this case; and here is no more reason why it should defeat identity in the case of a natural or metaphysical property (X) and goodness (Y).


GE Moore, Principia Ethica, 1903.

Fred Feldman, 'The Open Question Argument: What It Isn't; and What It Is', Philosophical Issues, Vol. 15, Normativity (2005), pp. 22-43.

  • "The intelligibility of the question does not defeat identity in this case..." Is my answer the explanation what does this mean?
    – rus9384
    May 15 '18 at 22:21

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