Complexity of value is the thesis that our preferences, the things we care about, don't compress down to one simple rule, or a few simple rules. To review why it's important (by quoting from the wiki):
- Caricatures of rationalists often have them moved by artificially simplified values - for example, only caring about personal pleasure. This becomes a template for arguing against rationality: X is valuable, but rationality says to only care about Y, in which case we could not value X, therefore do not be rational.
- Underestimating the complexity of value leads to underestimating the difficulty of Friendly AI; and there are notable cognitive biases and fallacies which lead people to underestimate this complexity.
I certainly agree with both of these points. But I worry that we (at Less Wrong) might have swung a bit too far in the other direction. No, I don't think that we overestimate the complexity of our values, but rather there's a tendency to assume that complexity of value must lead to complexity of outcome, that is, agents who faithfully inherit the full complexity of human values will necessarily create a future that reflects that complexity. I will argue that it is possible for complex values to lead to simple futures, and explain the relevance of this possibility to the project of Friendly AI.
The easiest way to make my argument is to start by considering a hypothetical alien with all of the values of a typical human being, but also an extra one. His fondest desire is to fill the universe with orgasmium, which he considers to have orders of magnitude more utility than realizing any of his other goals. As long as his dominant goal remains infeasible, he's largely indistinguishable from a normal human being. But if he happens to pass his values on to a superintelligent AI, the future of the universe will turn out to be rather simple, despite those values being no less complex than any human's.
The above possibility is easy to reason about, but perhaps does not appear very relevant to our actual situation. I think that it may be, and here's why. All of us have many different values that do not reduce to each other, but most of those values do not appear to scale very well with available resources. In other words, among our manifold desires, there may only be a few that are not easily satiated when we have access to the resources of an entire galaxy or universe. If so, (and assuming we aren't wiped out by an existential risk or fall into a Malthusian scenario) the future of our universe will be shaped largely by those values that do scale. (I should point out that in this case the universe won't necessarily turn out to be mostly simple. Simple values do not necessarily lead to simple outcomes either.)
Now if we were rational agents who had perfect knowledge of our own preferences, then we would already know whether this is the case or not. And if it is, we ought to be able to visualize what the future of the universe will look like, if we had the power to shape it according to our desires. But I find myself uncertain on both questions. Still, I think this possibility is worth investigating further. If it were the case that only a few of our values scale, then we can potentially obtain almost all that we desire by creating a superintelligence with just those values. And perhaps this can be done manually, bypassing an automated preference extraction or extrapolation process with their associated difficulties and dangers. (To head off a potential objection, this does assume that our values interact in an additive way. If there are values that don't scale but interact nonlinearly (multiplicatively, for example) with values that do scale, then those would need to be included as well.)
I'm going to deploy what I call the Wittgenstein Chomsky blah blah blah argument. Philosophy is just words in English; there is little ultimate meaning we are going to find here unless we declare our mathematical axioms. Already most of the views here seem reconcilable by redefining what exactly the different words mean.
To answer the question: some things can be proven objectively true, some things can be proven objectively false, some things can be proven to be undecidable. A fact is a true statement that follows from your given system of axioms. I personally am unsure if most moral principles or meta ethical systems can be declared objectively true or false with a standard ethical system, but I'm not going to take it seriously until a theorem prover says so. We are never going to convince each other of ultimate philosophical truth by having conversations like this.
I suppose this makes me an anti-realist, unless someone feels like redefining realism for me. :D
Again, it feels like I am missing something... http://plato.stanford.edu/entries/truth-axiomatic/ helped a little.