Is ethical truth something absolute and fixed for all time, in the same way that 2+2=4 will always be true, or is it historically and culturally specific - or is there no such thing as "ethical truth" at all? What is the precise meaning of the word "ought"? These sorts of questions fall under the scope of Metaethics. The Internet Encyclopedia of Philosophy defines metaethics as follows: "..the study of the origin and meaning of ethical concepts. When compared to normative ethics and applied ethics, the field of metaethics is the least precisely defined area of moral philosophy. Three issues, though, are prominent: (1) metaphysical issues concerning whether morality exists independently of humans; (2) psychological issues concerning what motivates us to be moral; and (3) linguistic issues concerning the meaning of key ethical terms ..."