Here's an excerpt:
In his essay “The Subjectivity of Values”, J.L. Mackie aims to show that values are not built into the structure of the universe. He begins by clarifying his position, addressing possible reactions and trying to prevent misunderstandings. Some would reject Mackie’s thesis as being morally subversive, others would accept it as a platitude, and still others would say that the question of whether there are objective values is itself illegitimate. Mackie’s thesis applies to all purportedly objective values, not just moral ones. Also, his thesis is a second-order rather than a first-order claim: It states that our values have nothing objective corresponding to them, but one who accepts this claim is not thereby committed to adopt any particular attitude towards private conduct or public policy. One can think that values are ultimately subjective while still valuing things, practices, or states of affairs—or perhaps not valuing much of anything at all—because valuing something does not presuppose that valuing it has an ontological ground.