Who decides societal morality?
This question is prompted by another thread regarding capital punishment. There has been a lot of talk regarding people living within what's moral in society. (Yes, Tigger plays a big part in the inspiration for this question.) So, it got me thinking... while I do agree that society should have some level of a moral bar, where is that bar? Who decides? How is it decided?
Is it a set measure that exists whether people like it or not? Is it a "majority rules" kind of thing... which would make morality a moving target of sorts as times change?
Note: This question pertains to how we set the bar, not what the bar is.