- This article is part of Desire Utilitarianism
G.E. Moore argued that it is impossible to reduce value properties in general, and moral properties in specific, to some sort of natural properties.
Desire utilitarianism reduces value properties to natural properties.
Specifically, saying that X is 'good' means saying that 'there exists reasons for action for bringing about or preserving X'. Similarly, calling X 'bad' means that 'there exists reasons for action for avoiding or eliminating X'.
Furthermore, desire utilitarianism holds that desires are the only reasons for action that exist. Consequently, any claim about X being 'good' can only be true if and only if there are desires that will be fulfilled by bringing about or preserving X. In the absence of desires, there are no value.
G.E. Moore defends his Naturalist Fallacy by appeal to his Open Question Argument
The open question argument takes any case in which somebody wishes to argue that A is defined as B and asks, "X is A, but is X, B?" For example, "X is pleasure, but is X good?" If the question makes sense - if there is no trivial answer to the question, then this is meant to show that B cannot be reduced to A. Or, in this case, that good cannot be reduced to pleasure.
However, Moore's "open question argument" falls victim to the Masked Man Fallacy.
Imagine a case in which there is a masked man robbing travellers on the nearby streets. It is quite possible for a person to know who his neighbor is, while at the same time he does not know who the masked man is, even though (as it turns out) his neighbor is the masked man.
In other words, "Jones is my neighbor, but is Jones the masked man?" is an open question. The fact that this open question exists does not disprove the claim that Jones is the masked man.
Similarly, the fact that it is an open question whether something is good does not disprove the claim that it is good.
In order to disprove the claim that X is good, for any X, somebody such as Moore needs to point out something that is true of X but false of 'good', or true of 'good' but false of X. This is true in the same way that defending the masked man requires proving that something is true of the masked man that is not true of the neighbor, or true of the neighbor that is not true of the masked man. This will prove that they are not identical.
Another area where the so-called 'naturalistic fallacy' can come into play is in the question of reducing mental properties to properties of the brain. Some scientist might want to report that 'pleasure' is a stimulation of the limbic section of the brain. However, it will still be the case that the agent knew he was experiencing pleasure, but he did not know that he was experiencing stimulation of the limbic section of the brain. In other words, "I am experiencing stimulation of the limbic section of the brain, but am I experiencing pleasure?" remains an open question.
However, the fact that the agent does not know that pleasure involves stimulation of the limbic center of the brain is no argument against the claim that pleasure is the stimulation of the limbic section. The area of brain science is another area where the 'masked man fallacy' defeats the 'naturalistic fallacy'.
With the masked man fallacy defeating the naturalistic fallacy, we no longer need to worry about the alleged 'impossibility' of reducing value properties to relationships between states of affairs and desires - just as we do not need to worry about the alleged 'impossibility' of reducing pleasure to stimulations of the limbic system. We find no solid objection to such a project here.