Sean Carroll on Sam Harris' TED talk:
He starts by admitting that most people are skeptical that science can lead us to certain values; science can tell us what is, but not what ought to be. There is a old saying, going back to David Hume, that you can’t derive ought from is. And Hume was right! You can’t derive ought from is. Yet people insist on trying.
Harris uses an ancient strategy to slip morality into what starts out as description. He says:
Values are a certain kind of fact. They are facts about the well-being of conscious creatures… If we’re more concerned about our fellow primates than we are about insects, as indeed we are, it’s because we think they are exposed to a greater range of potential happiness and suffering. The crucial thing to notice here is that this is a factual claim.
Let’s grant the factual nature of the claim that primates are exposed to a greater range of happiness and suffering than insects or rocks. So what? That doesn’t mean we should care about their suffering or happiness; it doesn’t imply anything at all about morality, how we ought to feel, or how to draw the line between right and wrong.
Morality and science operate in very different ways. In science, our judgments are ultimately grounded in data; when it comes to values we have no such recourse. If I believe in the Big Bang model and you believe in the Steady State cosmology, I can point to the successful predictions of the cosmic background radiation, light element nucleosynthesis, evolution of large-scale structure, and so on. Eventually you would either agree or be relegated to crackpot status. But what if I believe that the highest moral good is to be found in the autonomy of the individual, while you believe that the highest good is to maximize the utility of some societal group? What are the data we can point to in order to adjudicate this disagreement? We might use empirical means to measure whether one preference or the other leads to systems that give people more successful lives on some particular scale — but that’s presuming the answer, not deriving it. Who decides what is a successful life? It’s ultimately a personal choice, not an objective truth to be found simply by looking closely at the world. How are we to balance individual rights against the collective good? You can do all the experiments you like and never find an answer to that question.
Harris is doing exactly what Hume warned against, in a move that is at least as old as Plato: he’s noticing that most people are, as a matter of empirical fact, more concerned about the fate of primates than the fate of insects, and taking that as evidence that we ought to be more concerned about them; that it is morally correct to have those feelings. But that’s a non sequitur.