The following is my summary of a long and frequently frustrating debate on Facebook between myself, another atheist, and a Christian. I changed the names for some degree of privacy.
"The evolution of morality is a pretty well researched question with solid evolutionary answers. A better argument for the existence of something along the lines of God is awareness itself. To the best of my knowledge, science has so far been unable to offer an explanation of why anyone's aware of anything. Nor does it offer a satisfactory explanation of why I happen to be aware of only me - and not any of the other billions of creatures in existence.
In my mind, questions about the origin of awareness beg an answer that must point somewhere outside of what we currently know as nature, or at the very least requires augmentation of our knowledge of nature.
However, jumping briskly from these questions to "God exists as depicted in the Bible, and he sent Jesus to atone for our sins" is a gross violation of rationality, and it is only possible if you first assume that the Bible contains truth, and THEN proceed from that point onward, rather than considering the truth of the Bible on its own. It must be clear to any imaginative mind that IF a spiritual world exist, it might take any number of forms, and that a book originated by an organization that is obviously in the business of power and influence is NOT a source to be trusted at all.
Now, as far as Evelyn's faith goes, I think it is fairly clear at this point, and has been shown numerous times, that:
(1) Evelyn's faith is irrational, and she's proud of that. She has exclaimed several times that her world is not limited to probabilities between 0 and 1, and that it isn't limited by cold logic. She might as well have said directly that her world involves fairy tales. These were clear admissions that rationality is not important to her. And not just when it comes to religion: she actually went further and stated that even knowledge about the world is not important to her, preferring the bliss of ignorance to scientific pursuit of knowledge. (This, while at another point referring to her credentials as a scientist.)
(2) The purpose of Evelyn's faith is to give her comfort. She has stated several times that the reason she believes is because it makes her feel good, and she would like others to believe because it would make others feel good. At no time nor at any point did she use any argument that would assert that her faith is "true". When asked to evaluate the probability that her faith is true, she flatly declined. This indicates she might not even actually believe her faith is true, she just enjoys a thought process that assumes it is true, and she wishes to preserve that thought process for the comfort it provides.
(3) Evelyn believes that atheists live in mental anguish where they suffer from not having a comfortable answer about the nature of the universe. Evelyn fails to understand that it isn't necessary to believe in a detailed story of a God in order to be comfortably at ease with the Universe.
If any progress is to be made in helping Evelyn understand where Isaac and others like him are coming from, it would be in clearing up the misconception in paragraph (3) above. The reason Evelyn chooses her faith is emotional. The emotions involved are a sense of bliss if the faith is retained, and fear of uncertainty and emptiness if it isn't. Because her reasons are emotional, she will actively evade any attempts to apply reason that could threaten her faith.
I do not think that reason and logic alone can put even a chink in her armor. The armor is auto-deflecting and self-repairing, and she has been practicing those self-repairs her entire life.
If you want her to understand where you are coming from, the first order of business would be to explain, in EMOTIONAL terms, what helps you, as an atheist, to sleep peacefully at night. What makes you not perceive the world as cold and empty. What gives you the same emotional assurance as the bliss she gets from "knowing" that God is there to love her and guide her.
For atheists, who are used to thinking logically, this is a pretty tall order. Not every atheist might even have these emotional issues resolved. This is because atheists are ascetic thinkers, driven by principle, not comfort. We are willing to endure mental discomfort in order to pursue Truth.
Most people who are religious, however, are not ascetic thinkers. They don't find refuge in religion because they're driven by a noble principle. Instead, such people put more stock in mental comfort. They may in fact have given up on understanding the world in the first place, and so could not care less if their world view is further distorted. They may not even be able to tell the difference between a distortion and truth. And they don't care - as long as what they believe makes them comfortable."