Open-question argument

The Open Question Argument is a philosophical argument put forward by British philosopher G. E. Moore in §13 of Principia Ethica (1903), to refute the equating of the property good with some non-moral property, whether naturalistic (e.g. pleasure) or meta-physical (e.g. God's command). The argument takes the form of syllogistic modus tollens:

(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 (i.e. it is an open question).

(Conclusion) X is not (analytically equivalent to) good.

The type of question Moore refers to in this argument is an identity question, "Is it true that X is Y?" Such a question is an open question if a conceptually competent speaker can question this, otherwise the question is closed. For example, "I know he doesn't eat meat but is he a vegetarian?" would be a closed question. However, "Is the morning star the same thing as the evening star?" is an open question; the question cannot be deduced from the conceptual terms alone.

The Open Question Argument claims that any attempt to identify morality with some set of observable, natural properties will always be an open question (unlike, say, a horse, which can be defined in terms of observable properties). Moore further argued that if this is true, then moral facts cannot be reduced to natural properties , and that therefore ethical naturalism is false.

Objections and rejoinders

Begging the Question

The idea that Moore begs the question (i.e. assumes the conclusion in a premise) was first raised by W. Frankena. Since analytic equivalency, for two objects X and Y, logically results in the question "Is it true that X is Y?" being meaningless (by Moore's own argument), to say that the question is meaningless is to concede analytic equivalency. Thus Moore begs the question in the second premise. He assumes that the question is a meaningful one (i.e. that it is an open question). This begs the question and the open question argument thus fails.

In reponse to this, 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.

(Premise 1) If X is good, then X will in itself motivate an individual to pursue it.

(Premise 2) A cognitively sound and competent speaker of English (or whatever language the OQA is made in) can understand that Action X* produces X, yet not pursue X*.

(Conclusion) X is not (analytically equivalent to) good.

This evidently presupposes the internalist theory of motivation (i.e. a belief can itself motivate), in contrast to the externalist theory of motivation, also known as the Humean theory of motivation (i.e. both a belief and a desire are required to motivate). If it not the case that an motivation is internalist, then this reformulation fails.

Meaningful Analysis=

The main assumption within the open question argument can be found within premise 1. It is assumed that analytic equivalency will result in meaningless analysis. Thus, if we understand Concept C, and Concept C* can be analysed in terms of Concept C, then we should grasp concept C* by virtue of our understanding of Concept C. Yet it is obvious that such understanding of Concept C* only comes about through the analysis proper. Mathematics would be the prime example: mathematics is tautological and its claims are true by definition, yet we can develop new mathematical conceptions and theorems. Thus, X (i.e. some non-moral property) might well be analytically equivalent to the good, and still the question of "Is X good?" can be meaningful. Ergo premise 1 does not hold and the argument falls.

Frege Sense-Reference Distinction

There is a difference between the sense of an object and the reference (i.e. the object itself). Thus, we can understand a claim like "goodness is identical with pleasure" as an a posteriori identity claim on a par with "Water is H₂O". The question "This is H₂O but is it water?" is intelligible and so, in that limited sense, whether or not water is H₂O is an open question, note that this does not address the issue of significance. But that does not lead us to conclude that water is not H₂O. "Water is H₂O" is an identity claim that is known to be true a posteriori (i.e., it was discovered via empirical investigation). Another example is "redness" being identical to certain phenomena of electromagnetism. This is discovered by empirical investigation.

Similarly, many moral naturalists argue that "rightness" being the property of "maximizing utility" is an a posteriori truth because we invoke rightness and wrongness to explain certain empirical phenomena, and then discover a posteriori that maximizing utility occupies the relevant explanatory role. For example, they argue that since right actions contingently have certain effects e.g. being causally responsible for a tendency towards social stability—so it follows we can fix the term "right" refer to the empirical description "the property of acts, whatever it is, that is causally responsible for their tendency towards social stability." With this description for "right," we can then investigate which acts accomplish this: e.g. those actions that maximize utility. We can then conclude that we have learned that "right" refers to "maximizing utility" through a posteriori means.

A rebuttal to this is that trying to find an a posteriori means to learn what morality is, such as in the above example, run into the Open Question Argument all over again. For example, it may be that we learn a posteriori that "redness" is identical to having certain electromagnetic properties, but first we must attach an initial, a priori definitional reference to the term "redness"--e.g. "that which produces the sensation 'red' to normal perceivers under standard conditions." Because the Open Question argument applies to all a priori statements of morality, it applies to the initial identity claim that "rightness" refers to "the property of acts, whatever it is, that is causally responsible for their tendency towards social stability." Whether rightness refers to that is an open question. The moral non-naturalist could argue that any attempt to make an initial identity reference for naturalistic morality is susceptible to the Open Question Argument.

Analytic equivalence

A moral naturalist could respond to the above claiming that "rightness" is analytically equivalent (essentially, true by definition, much as 2 + 2 is equivalent to 4) to "the property of acts that is causally responsible for social stability," even if this equivalency does not appear obvious. From there, both sides could dispute the plausibility of such equivalence statements being true by definition.

Other objections

Critics of Moore's arguments sometimes claim that he is appealing to general puzzles concerning analysis (cf. the paradox of analysis), rather than revealing anything special about value. Other responses appeal to the Fregean distinction between sense and reference, allowing that value concepts are special and sui generis, but insisting that value properties are nothing but natural properties (this strategy is similar to that taken by non-reductive materialists in philosophy of mind).