Open-question argument

Description

The Open Question Argument is a philosophical argument put forward by the British philosopher G. E. Moore in §13 of Principia Ethica. It sets out to demonstrate the predicate "good" cannot be defined using natural terms: Good cannot be called blue, or rough, or smooth, or smelly - it lacks natural properties. That being said, "good," Moore argued, is not a supernatural property. He merely said that trying to define it using natural terms led to the "Naturalistic fallacy". Moore argues that the question of "What is good?" is an open one.

The argument hinges on the nature of statements such as "Anything that is pleasant is also good" and the possibility of asking questions such as "That thing is pleasant but is it good?" According to Moore, these questions are open and these statements are significant; and they will remain so no matter what is substituted for "pleasure". Moore concludes from this that any analysis of value is bound to fail. In other words, if value could be analyzed, then such questions and statements would be trivial and obvious. Since they are anything but trivial and obvious, value must be indefinable.

Objections and rejoinders

A Posteriori Identities

An important response to the open question argument by contemporary ethical naturalists (e.g., Peter Railton) is to 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 a certain phenomenon 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 the above, 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 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 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).