In the end, though, the difference between atheists and believers lies less in the answers to such [philosophical] questions than in the degree of closure required from those answers. I, as an atheist, am happy to say, ‘I do not know what First Cause is, or even if there is one. It may be that one day we discover the answer to that. Or it may be that we never will. For now I am happy to keep an open mind, accept our ignorance of First Cause and live with the uncertainty of not having one’.
Believers are reluctant to go down that road. They insist that there must be a First Cause and that it must take the form of God. They find it difficult to live with the uncertainty about First Cause that comes with non-belief. In Peter Stannard’s words they know – they have to know – that God exists. Which is why that which divides believers and atheists is a matter not simply of philosophy but also of psychological temper. […]
The difference between believers and atheists in not, then, that one picks and chooses moral values, while the other simply receives them from God. It is that I, as an atheist, accept that values are humanly created, while believers, having humanly chosen what is good and bad, then alienate this decision to God, because that seems provide those values with greater authority. The difference, in other words is between those who are happy to accept the unnerving thought that we live by our own moral standards and those who have a need to set their ethics in concrete by invoking the authority of God.
The whole post, along with the discussion in the comments, is worth a read.