As part of this course we are learning about J. L. Mackie's view of Moral Scepticism by reading his piece The Subjectivity of Values. The main focus of this post is to discuss his argument from queerness but in order to understand this argument it helps to have a little bit of the overall view in mind. By Moral Scepticism, Mackie generally means that he does not believe in objective moral values. His position however is a little more complicated. He believes that moral values are the kind of thing that would be objectively true or false but they are all false. So when making a claim such as, "X is wrong." it is like saying, "Getting up in the middle of the night will result in being eaten by the monsters under your bed." because both claims don't have a referent. There are no monsters under your bed, so the sentence is false. Similarly, there is no such thing as right or wrong. So moral claims are simply false.
Now, Mackie makes arguments for why the view above would be plausible or at least why other views would not be plausible. The Argument from Queerness does the latter by attacking the Objectivist's intuition. All Objectivists at some point need to fall back on some sort of intuition-- that there is a fact of the matter and each person should be able to intuit it. Mackie states, "If there were objective values, then they would be entities or qualities or relations of a very strange sort, utterly different from anything else in the universe." So, this sense of right and wrong is a very strange sort.
Let's consider some of the possibilities. On the one hand, moral intuition is not like sight, sound, taste, touch, or smell. All the senses seem verifiable. If there is a claim about how something feels; say it feels hard. There are comparisons and tests to determine what is harder than what. Sounds can be measured as waves and smells could at the microscopic level be split into individual molecules. So morals are "utterly different" from the senses. This seems quite clear. What are some things that might be similar though? Some might argue that math has the same sort of intuition. There aren't these physical things out there that make mathematical properties true but instead they are just there and they exist objectively. Some Objectivists would put morals in the same category. Some concerns with calling this a similarity would be how one solves arguments. In math, in general, if two rational people disagree about a proposition, there is a proof that would convince the opposing party to change his or her view. With any moral claim however, even something widely accepted such as, "Kicking babies for fun is wrong." doesn't have the same proof. This seems to put moral claims in a different category. The Objectivist will suggest numerous other possible similarities such as number, identity, necessary existence, and infinite expansion of time or space. But Mackie claims that all of these (some with a fair amount of effort) can be shown to be as they are empirically although he does not do this in this argument. The claim of "utterly different" may come into question but we have at least clearly established different.
If we accept that this first part of Mackie's claim is true, that the intuition is a very strange sort there is still the question as to whether it is reasonable to have this special capacity for moral intuitions. Mackie however finds this to be a lame excuse and compares such intuition to Plato's forms. It just doesn't make sense to believe there to be this special kind of intuition when there is nothing to back it up. The simpler explanation that moral claims are objective but false (like astrology for instance) is a plausible explanation and the one that Mackie endorses.