|Nietzsche sans God|
A number of atheists disagree with Harris and do not believe, in the absence of an all-knowing, all-powerful, all-loving God, that there could be OMVs. And, philosophical naturalists who, definitionally, believe "nature" is all there is, and science is the means to analyze it, mostly do not believe one of the things we find in nature is value. That is, I can weigh and measure and analyze the substance of a rock, but in the weighing and measuring and analysis I do not see "value."
Troy Jollimore, in his review of Harris's The Moral Landscape, writes: "secular liberals have tended to accept a form of moral skepticism or relativism, according to which there are no moral truths at all other than those that can be asserted within a particular cultural context. The idea of an objective moral truth, then, is something that secularists have largely abandoned to believers. And the idea that science, in particular, might have something to say about questions of morality is one that few contemporaries are willing to take seriously. People who go searching for answers to questions of value often simply assume both that science will not help them and that religion is the only alternative." Let's correct that last statement to read: religion and philosophy are the only alternatives. With this I agree. But Harris does not. He thinks that science can tell us about values. And in this he is wrong. (And by "wrong" I am not making a scientific claim.)
A proper understanding of morality, he argues, will reveal that it falls well within the area of inquiry that is governed by science. For moral questions are questions about well-being, and questions about well-being are, in essence, empirical questions about what makes humans and other conscious organisms flourish and thrive. "Questions about values—about meaning, morality, and life's larger purpose—are really questions about the well-being of conscious creatures," he announces on page one. "Values, therefore, translate into facts that can be scientifically understood.""
False, because Harris begs the question. "Well-being" is itself a value. To say something has "well-being" is to make a value judgment. Does, e.g., the deer lying in pain by the roadside have "well-being" as it loses x pints of blood? Science can quantify the blood loss and identify the broken bones. But "well-being," if it exists, is a non-natural property and thus cannot, ipso facto, be studied by science.
Watch this (here it comes again). For Harris "it is equally mistaken, he suggests, to insist that questions of well-being cannot be addressed by empirical research methods. There are, he says, discernible and indeed undeniable differences between an extremely good human life and an extremely miserable one; and there is no good reason for refusing to view those differences as both real and, in the relevant sense, objective." But this begs the question as to what "extremely good life" and "extremely miserable life" might mean, since such qualities are not found under the microscope. Harris already knows or assumes, somehow, what an "extremely good life" is and with this pre-scientific knowledge judges a life to be "good" or "miserable."
I think Harris sees the importance of there being OMVs. As an atheistic naturalist he knows many of his kind deny their reality. See, e.g., atheistic naturalist Joel Marks here, who reasons (correctly) that, on atheism, morals do not even exist. In this regard the idea of a "moral landscape" is an illusion and, like Nietzsche's madman, we're cast adrift on a sea with an infinite horizon. Welcome to atheism.