Reddit reviews On the Genealogy of Morality

At the outset, please note that this topic is exceedingly slippery. I am convinced that the most efficient way to understand these issues is through the study of philosophy of ethics.

> Where do atheists get their [sense of] morality?

Nature, nurture, and the phenomenological self-model.

> What defines the "good" and "bad" that has
permeated much of human society?

Easy: notice that personal definitions of morality between individuals immersed in the same culture tend to strongly overlap (e.g., most moderns consider rape to be "bad").

From this considerable volume of data, it is fairly simple to construct principles that adequately generalize these working definitions, such as "promote happiness", and "mitigate pain".

> [If you're not caught, why not murder? Why donate to charity? Does might make right?]

These questions appear to have both practical and intuitive solutions.

What are you trying to understand?

> How do atheists tend to reconcile moral relativism?

What do you mean?

> Barring the above deconstructions, how do atheists account for morality?

Moral theories largely attempt to bridge the gap between descriptive facts and normative commands:

• Kant argued that norms are not discovered via our senses, but are simply axiomatic principles.
  
• Rawls argued that norms are the product of a hypothetical agreement in which all ideally rational humans would affirm certain values (Social Contract) if they didn't know their fate in advance (Veil Of Ignorance).
  
• Mill argued that norms are best expressed through the need to increase pleasure and decrease pain.
  
• Parfit argued that these three approaches don't really contradict one another.
  
• Nietzsche argued that norms and artistic tastes are the same.
  
• Mackie argued that norms are human inventions that include social welfare considerations.
  
  

Shameless self-reply: I like this translation of GM, this translation of BGE, and this translation of Z. And it's not just because a professor of mine is the series editor, they're really good.