You see morality as something beyond just a choice? Yes, once you set down some principles, you rationally derive the morality of various situations from that, but the laying down of the original principal, where does that come from? It is just declared, is it not? "I hold this truth to be self-evident, that X is a moral principle."
If I have that wrong, I would LOVE to know it!
If I'm understanding what you're saying here correctly (which is far from certain), I agree with you that what moral systems I endorse depend on what I assign value to. If that's all you meant by morality not being fundamentally rational, then I don't think we disagree on anything here.
Suppose I have choice between the following:
A) One simulation of me is run for me 100 years, before being deleted.
B) Two identical simulations of me are run for 100 years, before being deleted.
Is the second choice preferable to the first? Should I be willing to pay more to have multiple copies of me simulated, even if those copies will have the exact same experiences?
Forgive me if this question has been answered before. I have Googled to no avail.