Incommensurable values and moral revisionism in Mulgan’s theory

In a previous post on Tim Mulgan’s Purpose in the Universe: The Moral and Metaphysical Case for Ananthropocentric Purposivism, I argued that the moral argument for AP seems to be self-undermining. Confidence in certain moral convictions is needed to justify objectivism about value; objectivism about value, in turn, is needed to justify AP. But if AP is true, it seems that we should not be confident in any of our moral convictions. And if AP implies extreme moral skepticism, Mulgan’s argument falls apart.

I think this objection can be avoided, but only at some cost to Mulgan’s revisionist ambitions for a moral theory consistent with AP. The saving move is to allow multiple incommensurable values. Mulgan follows Joseph Raz in defining incommensurable values as follows: “A and B are incommensurable if it is neither true that one is better than the other nor true that they are of equal value.”

Suppose that the objective values are incommensurable and include both human-centred values like virtue, pleasure and justice and non-human-centred values like beauty, intelligibility, and the elegance of natural law. Because these values are incommensurable, each would play a role in selecting a universe to actualize (either directly, as in axiarchic forms of AP, or indirectly, as in theistic forms). Only universes that instantiate all of these values would be actualized, and we know from our experience of this world that a beautiful, intelligible and elegant universe that is also hospitable to human-centered values will certainly contain horrendous evils. So if values are incommensurable, we can take our convictions about human-centred and non-human-centred values at face value at both ends of the argument for AP.

Mulgan believes that AP implies a highly revisionist account of human morality; once we understand the true, non-human-centred order of values, our views on the right and the good must be radically revised. But Mulgan’s argument for AP only succeeds if AP’s moral implications are quite conservative. The truth of AP would actually make very little difference to the content of a correct moral theory, because the non-human-centred values do not come into conflict with familiar human-centred values. AP may explain the circumstances in which we find ourselves theorizing about morality, but it sheds no light on the object of that activity.