Error Theory is a philosophical concept that suggests moral statements are fundamentally flawed because they claim to describe objective moral facts that do not exist. According to this theory, when people make moral claims, they are always mistaken, as there are no true moral values or properties in the world. This theory is often associated with the work of philosophers like J.L. Mackie, who argued that our moral beliefs are based on subjective feelings rather than objective truths. Error Theory challenges the validity of moral discourse, asserting that discussions about right and wrong are ultimately misguided.