Though I am a Buddhist and therefore not very well described as an atheist (but not strictly wrongly described as an atheist depending on how we define God) I believe that the observable consequences of our actions ARE the Karmic results of our actions. Any atheist (or Christian, or Muslim, or Jew, or Hindu, or Indigenous Religious person) that does not try to push irrational beliefs (and yes, Atheism is irrational because it makes an unprovable claim) on others, and who also tries to cultivate a deep love and sense of oneness with all sentient beings of Nature gets a +++ in my book.
I kind of want to set the record straight atheists just don't believe in a god they are not inherently intelligent or always factual just like not all Christians are stupid, naïve, slavery supporting, women hating people there just ignorant of the stories they claim to revere now it just so happens that atheists tend to be smart and have the ability to use critical thinking but that's not a tenant of atheism, atheism dosean't have tenants which makes it the most legitament and beautiful religion (if I want to call it such and I don't know a better word for it)
Since we have basically proven the theory of evolution, Atheism is a sound un-religious philosophy in the modern world. Atheist don't cause wars in the name of God. Atheist look at everything with sound and scientific research instead of just saying because God says so. Atheist want to solve a problem not get in to heaven.
Atheism, being grounded in reality, rather than the supernatural, is a perfectly sound philosophy in the modern world. Atheism is in essence, a statement that while one does not understand the world and its coming into existence, one is unwilling to accept the notion of a god or gods behind it. At one time, it may have been unfathomable, that the world could be created from nature, but with modern science, the modern world is able to accept scientific reasoning in place of god.
But it's not a philosophy in and of itself. It has no core principles, no particular system of thought.
One cannot study atheism, or use atheism as a guide to how they should behave.
Simply put, two atheists match in a set of beliefs they don't hold, but the beliefs they do hold don't necessarily match at all.