I figure morality as a topic is popular enough and important enough and related-to-rationality enough to deserve its own thread.
Questions, comments, rants, links, whatever are all welcome. If you're like me you've probably been aching to share your ten paragraph take on meta-ethics or whatever for about three uncountable eons now. Here's your chance.
I recommend reading Wikipedia's article on meta-ethics before jumping into the fray, if only to get familiar with the standard terminology. The standard terminology is often abused. This makes some people sad. Please don't make those people sad.
I would not be in favor of wireheading the human race, but I don't see how that is connected to S. If wireheading all of humanity is bad, it seems clear that it is bad because it is bad for the people being wireheaded. If this is a wireheading scenario where humanity goes extinct as a result of wireheading, than this is also bad because of the hypothetical people who would have valued being alive. There is nothing about S that stops someone from comparing the normal life they would live with a wireheaded life and saying they would prefer the normal life. This is because these two choices involve different mental states for the person, and S does not in itself place any restrictions on which mental states would be better for you to have. Rather, it states that your own mental states are the only things that can be good or bad for you.
If you think S is false, you could additionally claim that wireheading humanity is bad because the fact that humanity is wireheaded is something that almost everybody believes is bad for them, and so if humanity is wireheaded, that is very bad for many people, even if these people are not aware that humanity is wireheaded. But it seems very easy to believe that wireheading is bad for humanity without believing this claim.
Just to make sure I understand your position: Imagine two universes U1, and U2,like the one in my original post, where P1 and P2 are unsure whether the gold cube exists. In U1 the cube exists, in U2 it does not, but they are otherwise identical (or close enough to identical that P1 and P2 have identical brain states). The Ps truly desire that the cube exist as much as anyone can desire a fact about the universe to be true. Do you claim that P1 is better off than P2? If so do you really think that this being possible is as obvious as that 2 + 2 =\= 3 ? If not, why would someone's well-being be able to depend on something other than their mental states in some situations but not this one? To me it seems very obvious to me that P1 and P2 have exactly equally good lives, and I am truly surprised that other people's intuitions and beliefs lean strongly the other way.
So would you argue that P2 shouldn't investigate whether the cube exists, because then he would find out that it doesn't and thus become worse off?