Alfred Jules Ayer was a key proponent of emotivism. In ethical theory, emotivism is considered as a non-cognitivism which contends that moral judgments are expressions of moral attitudes or opinion that cannot be true or false. As a branch of non-cognitivism, emotivism holds that moral judgments are expressions of positive or negative feelings. For an emotivist, a statement like “lying is wrong” has no meaning. Its meaning is no more than “yuk boo!” that expresses a negative feeling about something. Since it is not an empirical or analytical statement, we cannot justify whether it is right or wrong. At this point, we can see how emotivism and subjectivism are different. Unlike emotivism, subjectivism declares that we can justify right or wrong (moral judgments) through subjective states of individuals. Thus, a moral judgment such as “lying is wrong” could be right or wrong depends on the feelings and attitudes of the persons who think about such things.