The end of physic is our body's health.
Why, Faustus, hast thou not attain'd that end?
Are not thy bills hung up as monuments,
Whereby whole cities have escap'd the plague,
And thousand desperate maladies been cur'd?
Yet art thou still but Faustus, and a man.
Couldst thou make men to live eternally,
Or, being dead, raise them to life again,
Then this profession were to be esteem'd.
Physic, farewell! Where is Justinian?
--Marlowe, The Tragical History of Dr. Faustus
Sean Carroll has come out hard against Sam Harris's recent, mulish TED talk arguing that science can (and should?) tell us what to value. Carroll's response draws on the clear and simple principle that arguing that values are "objectively true" is like trying to square the circle. You can only succeed by annihilating your subject.
In the real world, when we disagree with someone else’s moral judgments, we try to persuade them to see things our way; if that fails, we may (as a society) resort to more dramatic measures like throwing them in jail. But our ability to persuade others that they are being immoral is completely unaffected — and indeed, may even be hindered — by pretending that our version of morality is objectively true. In the end, we will always be appealing to their own moral senses, which may or may not coincide with ours.Along the way, Carroll invokes Hume, to whom, it is commonly supposed, we owe the notion that "you can't derive an ought from an is." That's only partly true. Hume was getting at something more specific than a distinction between facts and values. He was trying to identify an error in rationalist thinking, in order to discredit that way of thinking, and the fact-value gap was his reductio. In the end, Hume didn't take much interest in deriving oughts from anything, and makes a poor champion for moral reasoning.
What most casual talk of "oughts" leaves out is a conditional premise. We ought to do X, if Y. We ought to eat better, if we want to live longer. We ought not to murder, if we believe that humans are ends in themselves -- or that we want to avoid a blood feud -- or that what goes around comes around -- or that God will be displeased with us for reasons he hasn't specified. Or some combination of these premises, which generally speaking flow from the way we imagine the nature of the world, which is to say, from our metaphysics.
The main danger of defining values as a sub-category of "empirical fact," as Harris does, is that it buries our metaphysical depictions in cement, where we can no longer call them up for reconsideration. It is an ideological move to say that one's values are universal, but it is nearly always a lie.
Why is it that we don't have ethical obligations toward rocks? Why don't we feel compassion for rocks? It's because we don't think rocks can suffer. And if we're more concerned about our fellow primates than we are about insects, as indeed we are, it's because we think they're exposed to a greater range of potential happiness and suffering.Overt concern with the fate of conscious (and pain-sensitive) agents is the sort of "universal moral truth" that seems obvious to those who have not surveyed the facts, which don't permit any such universality. The connection between "biological complexity" and sentience is a relatively new moral development. To an animist, mountains, trees, and bodies of water are all conscious. To a follower of Vedanta, everything in the world is a performance by the Godhead. Buddhist and Jain monks take care not to trod on the smallest beetle if they can help it. To define sentience in our modern way, as a function of neural complexity, and then argue that such sentience has always been everyone's concern, is incoherent.
There is no version of human morality and human values that I've come across that is not at some point reducible to a concern about conscious experience and its possible changes.
Discussions of meta-ethics must take into consideration that like all societies, we have our own metaphysical presuppositions that our ethical questions flow from. Today we are almost all humanists of a type, and this includes the Abrahamic religions. Secularists and monotheists alike take for granted that nature--matter--is passive and inert, and must be shaped by an intentional or "informational" force, whether God, man, or laws of physics and natural selection. This is not a matter of science, it is a matter of the metaphysical view that permits science (though there may be others).
Another important metaphysical precept that goes unexamined in Harris'analysis is Hobbesean social atomism, which underlies most moral thinking in the enlightenment tradition. But ecologists have been questioning for at least a century whether it makes any sense to value apes and dolphins, but not ants and plankton, when they each inhabit (with all of creation) the same web of causation. Perhaps it is not so crazy to have an ethical obligation towards rocks (in the form of coral reefs, for example), and perhaps this is area in which our primitive forebears have bested us in moral reasoning, by recogizing there is no extraneous, separable part of nature which we are not obligated to.
Harris does have some thoughtful things to say in this lecture. He makes a strong case for moral reasoning (though I would say it conflicts with his main thesis that morality is empirical.) And he makes the important point that we do have the right to judge other people's moral practices, such as shame killings. But ultimately his animus for religion drives him to illogical conclusions, such as the notion that what the Taliban lacks is sufficient science about "human flourishing" to make good moral choices1. By this standard, how much less moral must the ancient Greeks have been, who knew so much less science than the medieval Arabs. And how much more immoral the nomadic tribes that preceded them thoughout Africa and Asia minor. How immoral that first human couple must have been, in their African Eden!
What this hyper-utilitarianism (which marries Mill with the logical positivists) primarily accomplishes is this. It obviates the need to look reflectively at evil. When evil can be equated with a simple paucity of learning, like deficiency of a vitamin, there is no need to look within our own hearts for its seeds. All the world's darkness can be projected outwards onto people we couldn't have less in common with. We don't want to subjegate women; we don't want to tyrannize innocents; we don't want to convert the whole globe to our ethos, and exterminate those who resist (wait, scratch that last one.) Unfortunately it is far more likely that the opposite is true. Not even all the science of John Faustus can make us good, if we won't season it with introspection.
1It is noteworthy that Harris sets up the Dalai Lama as a paragon of virtue, based on his emphasis on compassion. But Tibetan Buddhism is just as old as Sunni Islam, which Harris places on the other pole, and while it may not be as reactionary in its anti-modernism as the Taliban, it does not embrace the metaphysical naturalism that Harris conflates with science.