Does Atheism Lead to Nihilism?

[SteveII]

An how does an atheist obtain ethics?

I personally obtain my ethics from whether or not an action harms another person. If what I do causes someone harm, it is self evident that what I am doing is wrong. I do not need a book to understand that.

When an individual cannot discern right from wrong on his own, and must have a book to tell him how to behave, then clearly he is lacking empathy much in the way that a sociopath does.

So your personal ethics come from harm avoidance. Isn't that highly subjective? Is it harm for all humans? Animals? Plants? What if there is a conflict between two people's best interest? How about the interplay between humans and animals? Do things like justice or fairness enter in?