@matigo Your framing is interesting. I’m confused because some parts seem to suggest you’re seeking a single atheistic foundation contra a single theistic foundation, but I don’t see either as something to assume.
- Why would there need to be a single reason for killing to be wrong?
- Why would two different atheists, or two different theists, necessarily share the same reason?
- How do wrong and evil relate?
It might prove fruitful to personalize the core question: When do you feel killing is wrong, and why? Then worry about everyone else after. ;)