"The original statement you disagreed with was "It is absolutely untrue that any human being operates purely on empirical evidence and fact."
There is NO empirical evidence to say killing is wrong. It is simply a Moral construct that we Believe....

We ALL Believe something...."

 Ok I see what you are saying.  I don't think to look at the ideas of right/wrong regarding ending human life as a belief but as an assessment of advantages or disadvantages of the action on an individual basis.  

 Killing is one of those right from one side, wrong from the other but not as clear cut as say algebra.