What are objective moral values? If moral values are objective there should be some way that we can come to agreement on what kinds of things that they are. Are they sui generis, non-natural properties with which we can somehow get into contact? If so, do such things exist? Alternatively, are objective moral values to be explained in terms of the natural, physical world rather than something non-natural, and if so, how do we explain their strange qualities?
In this paper I will examine J. L. Mackie’s argument from queerness, which is an argument against the existence of objective moral values. I will agree with Mackie that objective moral values as Mackie describes them, if they exist, are quite strange and unlike other properties in the universe. The peculiar qualities of objective moral values present a strange problem. If they are as Mackie terms them, ‘queer properties’, one’s approach to them turns on one’s acceptance of naturalism. That is to say, that if one embraces naturalism one will reject the existence of objective moral values, whereas one who embraces objective moral values will reject naturalism. So my conclusion will be that the argument from queerness is on suspect ground because it is dependent on an assumption of naturalism, but if objective moral values exist, this assumption is ungrounded.
Along the way, I will also look at attempts to argue that objective moral values are not queer properties but can be explained in terms of natural properties. In particular, I will examine David Brink’s response to Mackie’s argument from queerness, but conclude that it does not successfully avoid Mackie’s argument.