Eliezer,
I think the reason you're having trouble with the standard philosophical category of "reasons for action" is because you have the admirable quality of being confused by that which is confused. I think the "reasons for action" category is confused. At least, the only action-guiding norm I can make sense of is desire/preference/motive (let's call it motive). I should eat the ice cream because I have a motive to eat the ice cream. I should exercise more because I have many motives that will be fulfilled if I exercise. And so on. All this stuff about categorical imperatives or divine commands or intrinsic value just confuses things.
How would a computer program enumerate all motives (which according to me, is co-exensional with "all reasons for action")? It would have to roll up its sleeves and do science. As it expands across the galaxy, perhaps encountering other creatures, it could do some behavioral psychology and neuroscience on these creatures to decode their intentional action systems (as it had done already with us), and thereby enumerate all the motives it encounters in the universe, their strengths, the relations between them, and so on.
But really, I'm not yet proposing a solution. What I've described above doesn't even reflect my own meta-ethics. It's just an example. I'm merely raising questions that need to be considered very carefully.
And of course I'm not the only one to do so. Others have raised concerns about CEV and its underlying meta-ethical assumptions. Will Newsome raised some common worries about CEV and proposed computational axiology instead. Tarleton's 2010 paper compares CEV to an alternative proposed by Wallach & Collin.
The philosophical foundations of the Friendly AI project need more philosophical examination, I think. Perhaps you are very confident about your meta-ethical views and about CEV; I don't know. But I'm not confident about them. And as you say, we've only got one shot at this. We need to make sure we get it right. Right?
I can see that you might question the usefulness of the notion of a "reason for action" as something over and above the notion of "ought", but I don't see a better case for thinking that "reason for action" is confused.
The main worry here seems to have to do with categorical reasons for action. Diagnostic question: are these more troubling/confused than categorical "ought" statements? If so, why?
Perhaps I should note that philosophers talking this way make a distinction between "motivating reasons" and &q...
Barring a major collapse of human civilization (due to nuclear war, asteroid impact, etc.), many experts expect the intelligence explosion Singularity to occur within 50-200 years.
That fact means that many philosophical problems, about which philosophers have argued for millennia, are suddenly very urgent.
Those concerned with the fate of the galaxy must say to the philosophers: "Too slow! Stop screwing around with transcendental ethics and qualitative epistemologies! Start thinking with the precision of an AI researcher and solve these problems!"
If a near-future AI will determine the fate of the galaxy, we need to figure out what values we ought to give it. Should it ensure animal welfare? Is growing the human population a good thing?
But those are questions of applied ethics. More fundamental are the questions about which normative ethics to give the AI: How would the AI decide if animal welfare or large human populations were good? What rulebook should it use to answer novel moral questions that arise in the future?
But even more fundamental are the questions of meta-ethics. What do moral terms mean? Do moral facts exist? What justifies one normative rulebook over the other?
The answers to these meta-ethical questions will determine the answers to the questions of normative ethics, which, if we are successful in planning the intelligence explosion, will determine the fate of the galaxy.
Eliezer Yudkowsky has put forward one meta-ethical theory, which informs his plan for Friendly AI: Coherent Extrapolated Volition. But what if that meta-ethical theory is wrong? The galaxy is at stake.
Princeton philosopher Richard Chappell worries about how Eliezer's meta-ethical theory depends on rigid designation, which in this context may amount to something like a semantic "trick." Previously and independently, an Oxford philosopher expressed the same worry to me in private.
Eliezer's theory also employs something like the method of reflective equilibrium, about which there are many grave concerns from Eliezer's fellow naturalists, including Richard Brandt, Richard Hare, Robert Cummins, Stephen Stich, and others.
My point is not to beat up on Eliezer's meta-ethical views. I don't even know if they're wrong. Eliezer is wickedly smart. He is highly trained in the skills of overcoming biases and properly proportioning beliefs to the evidence. He thinks with the precision of an AI researcher. In my opinion, that gives him large advantages over most philosophers. When Eliezer states and defends a particular view, I take that as significant Bayesian evidence for reforming my beliefs.
Rather, my point is that we need lots of smart people working on these meta-ethical questions. We need to solve these problems, and quickly. The universe will not wait for the pace of traditional philosophy to catch up.