"I notice that you say 'my' moral code? Is there more than one moral code? Does your moral code obligate me? If so, why? If not, why not?"
You didn't know that some people have different moral codes than you? Have you been raised in a basement? Do you ever read books?
"You say that moral codes come from "the nature of our existence", and that if you don't follow your reason you will not last too long. I can think of many exceptions to that principle, for example people who do good and end up be killed for it, or people that do evil and prosper. Second, do I have a necessary moral obligation to survive? If so, then where does this moral rule come from, that is, to survive?"
Someone using their reason is being moral; someone who denies it is being immoral.
" If you are going to explain how evolution produced morality you can't posit a prior moral rule to explain it."
I never did. Read again.
"Third, regarding "the nature of our existence". Is there a fixed nature to our existence? "
Yes.
"f not, and if our nature changes (and Evolution teaches that it has and will continue to do), does morality itself then change?"
Evolution says no such thing. Nor did I.
How substantively different are they? Am I obligated by them?
Have you been raised in a basement?
No.
Do you ever read books?
Yes.
Someone using their reason is being moral; someone who denies it is being immoral.
Hmmmm. I'm going to let that one percolate for a while.
Cordially,