I heard one answer at a meeting of the University Atheists and Humanists at the University of Minnesota. The speaker had once been a Christian evangelist, but now was a traveling evangelist for atheism. He proclaimed liberation from the shackles of traditional religion. Another answer common in the university world is that faith as well as ethics has nothing to do with rationality, but is merely a personal choice. To suggest that there may be a God with whom we all have to deal is to intrude on others freedom.
Faith is a matter of personal taste, like enjoying theater or playing golf.
Philosopher Alvin Plantinga of the University of Notre Dame gives us much help in this area. Plantinga asks what ways of knowing there are. That is, scientific knowledge is based on logic and mathematics, on observation of the world physical world around us, and on memory. He goes on to suggest that there are other ways of knowing, such as the sense of the divine that all people seem to have. That is, religious experience is a valid source of knowledge.