Does Atheism Lead to Nihilism?

[pocaracas]

All the arguments based on "it is not really in our best interest to be selfish" only provides subjective morality and not any objective framework that goes beyond a certain sets of conditions. Depending on the society we live in, you can get wide variations of opinion between the "morality" of a host of actions.

Indeed, it's not a fixed, worldwide measure... your point?

How do you define "good" as in someone as a "good person"? In other contexts, we define something is "good" by how well it achieves its purpose. With naturalism, people have no intrinsic purpose--they are an assembly of atoms that experienced an unlikely chain of events. Morality becomes a matter of opinion and is relative and/or subjective. You can't leap from the "is" to the "ought".

A good person is one who does no unjustified purposeful harm to others. This harm can come in various shapes and forms which depend on the society.

In our evolution, was it always wrong to murder, rape or steal? Animals do these acts every single day without being "evil".

No... to the other tribes.
But it was always wrong to your own tribe.
Nowadays, a sort of global awareness exists, so a global ethics is developing. I'd say it's a noteworthy evolution of our species.... and, clearly, not all individuals are on par, there...

Some of you have mentioned societal goals (or any goals) that can help get from the is to the ought. What if someone does not want those goals--has no desire to do what others consider "good"? There is no objective grounds for saying that person is "bad". Of course everything goes smoother when everyone cooperated and does not kill, harm or steal. But that does not define what is good and thereby create an "ought".

Let's just say that the "objective" good is that which is agreed upon by the society.
An individual acting against this "objective" societal good is considered "objectively" bad and is punished, typically, by keeping him/her away from the rest of society, in jail.

For these reason, atheism seems to me to lead you to moral anti-realism (moral nihilism).

However, we all ACT like there is objective morality. Baby studies indicate that we are born with a rudimentary moral sense. Why do people engage in self-sacrifice for others (even to the point of death)--sometimes for people he/she has not met? This is certainly not biological evolution speaking.

Poor risk assessment, perhaps?
I'd say that each case is a case and they are not easily bundled into a neat answer.

Do we all act like there is objective morality because it is convenient or expedient or is there really objective morality? If there really is objective morality, it did not come by naturalistic means.

Convenient and expedient seem like two nice adjectives, here.