Non-cognitivism is the
meta-ethical view that ethical
sentences do not express
propositions (i.e.
statements) and thus cannot be
true or false (they are not
truth-apt). A noncognitivist denies the
cognitivist claim that "moral judgments are capable of being objectively true, because they describe some feature of the world." If moral statements cannot be true, and if one cannot
know something that is not true, noncognitivism implies that moral knowledge is impossible.