A More Interesting Open Question Argument

The orthodox interpretation of G.E. Moore’s Open Question Argument (OQA) has it that Moore set out to show that no satisfactory definition of goodness (or other evaluative/deontic terms) could be given. To define goodness in terms of some other property was to commit the naturalistic fallacy. The reason why such definitions are impossible is because any competent user of the concepts being employed in the definition can sensibly ask if such and such is good. One example employed by Moore, from Bertrand Russell, is that goodness is that which we desire to desire. But any competent user of the concepts “desire” and “goodness” can sensibly ask if what we desire to desire is good, whereas we cannot sensibly ask if what we desire to desire is what we desire to desire. So, “goodness” does not mean “that which we desire to desire”. The same argument can be run in terms of pleasure, or what God wills (or anything).

What one should notice about this version of the argument is that it’s about meanings of words. The argument does not entail anything about property identities, which should provide reductionists about moral ontology some relief. A hedonist could claim that she isn’t in the business of giving analytic identity claims, but rather goodness being the same thing as pleasure is a synthetic identity claim. Synthetic identity claims carry no commitment to synonymy between the terms denoting the things that are identical. So, water is identical to H2O, but “water” doesn’t mean the same thing as “H2O”. It should be noted, however, that the proponent of the OQA explained above would take this as a concession, because the synthetic reductionist is granting her conclusion.

A more interesting kind of OQA can be formulated with Leibniz’s law. Roughly, Leibniz’s law says that it is necessarily true that for any A and any B, A is identical to B iff every property that A has, B also has. And any property that B has, A also has. It seems like a relatively uncontroversial principle, until we get into the quantum domain, which doesn’t concern us here. So, bracketing any quantum concerns, we can formulate the new OQA using this principle. Let’s take goodness and happiness. It seems like we could sensibly doubt whether happiness is good, but we cannot sensibly doubt whether goodness is good. So, happiness has a property that goodness lacks, which is that happiness is such that we can sensibly doubt whether it is good. By Leibniz’s law, goodness and happiness are not identical, because happiness has a property that goodness lacks. What’s interesting about this argument is it gets you a metaphysical conclusion, unlike the OQA discussed before, which gets you a semantic conclusion. The OQA employing Leibniz’s law is more worrisome for synthetic reductionists, as it has to do with properties rather than meanings.

The OQA employing Leibniz’s law is not obviously unsound, and figuring out where it goes wrong is challenging. Personally, I think it goes wrong somewhere, but it isn’t obvious to me where exactly that is.


Further Reading:

Metaethics: A Contemporary Introduction by Mark van Roojen (Chapter 2)

  • Ben Crandall

    Hi, I don’t think I am anywhere near as familiar with these subjects as you are, but isn’t the property of being “sensibly doubted whether it is good” a purely intentional property… I mean someone could “sensibly doubt water was H2O” right?

    Maybe I am missing something (or maybe I am just rehashing the issues of Quine’s “Two Dogmas…,” but my reaction when I have heard of G.E.Moore’s open question argument was, so what? You can always ask whether two things are the same.

    But again, I am an amateur out of this and may be way out of my depth. Would appreciate any feedback though.

    • Here’s a better form of the argument:

      1. X wonders whether pleasure is good
      2. When X wonders whether pleasure is good, X does not believe that pleasure is good
      3. X does not believe that pleasure is good (from 1 and 2)
      4. X believes that goodness is good
      5. Goodness and pleasantness differ with respect to what X believes about them
      6. Leibniz’s law
      C. Goodness and pleasantness are distinct (From 5 and 6)

      That’s a more worked out form of the argument from van Roojen’s 2015 (chapter 2). The rationale is that there are relations that the property goodness does not enter with X that pleasantness does, so goodness differs from pleasantness by virtue of the fact that it can truly be said of pleasantness that X wonders whether it is good. So, even if the relationship is in an intensional context, where X is representing the properties under different modes of presentation (or whatever) the proponent of the argument is going to push back by saying relational properties constituted by intensional contexts on one side and particulars on the other (relations between doubts and objects of doubt in this case) still qualify as differences that are sufficient for the inference from Leibniz’s Law. With the water example, the proponent will say that when we identify water with H2O, the names pick out the same thing. So if X is thinking of water, she’s also thinking of H2O, even if it’s in a confused way. It’s analogous to a distinction in philosophy of perception between perception of S and perception as of S. So, when I look at a lake I perceive a body of H2O molecules, but I perceive of that lake as of a body of water.

      For my money, I’d go with the idea that when X believes that P is Q, that involves something more than just the relationship between X and the objects of her belief. It could be a proposition being represented in her mind within the context of a mode of presentation, where X is representing something in the ‘P’ way or the ‘Q’ way. If you’re a direct reference person you can say that X believes that P is Q but the way X is thinking of them is in the ‘P’ way. Or you could be a direct reference theorist and admit that ‘X believes that P is Q’ represents the Millian content but the use of the sentence has conversational implicature such that it communicates that X is thinking of Q under the name ‘P’ (or something close).

      So given that strategy, you’d want to deny 2 and 3. X could be wondering whether pleasure is good while believing it is. Instead of denying Leibniz’s Law in intensional contexts, which is implausible in my opinion, you can just deny that ‘X does not believe that pleasure is good’ follows from ‘x wonders whether pleasure is good’, because wondering whether pleasure is good is possible because X is thinking of pleasure in the ‘goodness’ way of thinking of it, and whatever that means is determined by the finer points of your theory of content.

    • I swear I responded to this comment when you left it, but it appears not to be here. I had a long explanation typed out in the old comment, but I’ll keep it brief: In intensional contexts, Leibniz’s Law doesn’t always fail to hold. Some think it usually holds in intensional contexts as well. The distinction between perceiving P and perceiving as P allows for Leibniz’s Law to hold in some intensional contexts. Perceiving P is just the fact that one is perceiving P, whereas perceiving that P is being presented with what one is perceiving in some manner or other. The former could be considered an intensional context, and Leibniz’s Law probably holds in that situation, whereas the latter is definitely intensional, and Leibniz’s Law probably fails to hold in that context.

      A more fleshed out version of the argument can be found in Mark van Roojen’s book, Metaethics, in chapter 2:

      1. Moore wonders whether pleasure is good.
      2. When you wonder whether something is good, you don’t believe that it’s good.
      3. Moore does not believe that pleasure is good.
      4. Moore believes that goodness is good.
      5. So goodness and pleasure differ with respect to what Moore believes about them.
      6. Leibniz’s Law.
      7. So, goodness and pleasure are distinct.

      The way I would critique the argument is by pointing out that ‘Moore believes that P is Q’ or similar sentences express more than just the fact that Moore has a belief involving P and Q. It could be that that sentence also expresses the fact that Moore believes a proposition with a particular mode of presentation (the ‘P’ way of thinking). Moore could also believe a Millian proposition with a specific way of thinking of it (the ‘P’ way). Or the sentence’s semantic content just is that Moore has a belief involving P and Q, but using it pragmatically enriches it such that it also involves Moore thinking in terms of Q’s name ‘P’. All of those options allow for us to resist the argument’s conclusion.

      The last move would open up the possibility of denying premises 2 and 3, because it wouldn’t follow from the fact that if one wonders whether P is Q then one does not believe that P is Q, since the context of wondering may involve thinking of Q using one of its names, ‘P’, while one also believes that P is Q by virtue of believing that Q is Q. In other words, one can wonder about Q through representing it in terms of its name ‘P’ while one also believes that P is Q without using the name ‘P’ in doing so.

      • Ben Crandall

        I had not realized you had responded to my comment until I just stumbled on it. But Alonzo Fyfe puts it more simply to me when he says Moore’s open question suffers from the “Masked Man Fallacy.”

        To use the wikipedia (home of philosophy):

        Premise 1: I know who Bob is.
        Premise 2: I do not know who the masked man is
        Conclusion: Therefore, Bob is not the masked man.

        The premises may be true and the conclusion false if Bob is the masked man and the speaker does not know that. Thus the argument is a fallacious one.


        Lois Lane believes that Superman can fly.
        Lois Lane does not believe that Clark Kent can fly.
        Therefore Superman and Clark Kent are not the same person.

        It seems to me Moore’s argument just plainly suffers from this fallacy… though to be honest more is a bit dry for my reading tastes so I mostly am aware of his argument through the secondary literature, and I haven’t revisited the original context of this discussion.

      • Ben Crandall

        Though to be honest, even about things like the identity relation, I have come to view it from a somewhat Wittgensteinian perspective as either a vacuous relation, or not a terribly useful one outside of simple logical diagrams.

        Am I identical to myself yesterday? In many ways yes, in many ways no. If that the same photon as before? In some ways yes and in some ways no.

        I love philosophy and I criticize people who ignorantly attack philosophy, but in some way language is never going to lose its ambiguity, referential terms will maintain a degree of inscrutability, etc.