The argument from queerness suggested by Mackie is one of his main arguments against moral realism. The following I would like to discuss is the details of this argument and the critique of it.
In advanced, I would like to define the meaning of “moral realism”. There are two tendencies of moral realism. One is naturalism, the other non-naturalism. Naturalistic moral realism states that moral facts exist like natural facts, either in relation or identical to. The non-naturalistic moral realism holds that moral facts exist unlike natural facts or any sensible things in the world, but some metaphysical entities.
The argument from queerness
Mackie’s argument from queerness mainly focuses on arguing against non-naturalistic moral realists, which consists of two parts, one metaphysical, the other epistemological. The former states that “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.”The second part is that in order to know this kind of strange properties, we need “some special faculty of moral perception or intuition, utterly different from our ordinary ways of knowing everything else.” Which Mackie thinks it is impossible.
For details, Mackie says that if a moral property exists, it must be able to be explained its features and we have to provide a way to know it. For example, if moral properties exist, what do they be made of? Can we taste them, touch them, or see them? It seems that these moral properties are so strange (/queer) and if we cannot observe them by our normal sense faculty, what other sense faculty can be used to know them?
Some intuitionists will claim that we can know it by “faculty of moral intuition”. That is, moral judgment is simply made by intuition. Mackie does not agree with this and says that it is implausible, “…the suggestion that moral judgments are made or moral problems solved by just