It has been assumed in most societies since the dawn of history that humans cannot be moral without God and religion. Sinnott-Armstrong, who is a Professor of Philosophy and Legal Studies at Dartmouth College, presents in this extended essay the modern view to the contrary.
More specifically he argues that a belief in God is not necessary for people to be good or for humans to realize that some acts are morally wrong. We do not need the fear of eternal damnation to behave in morally acceptable ways. This is then a treatise in moral philosophy in which Sinnott-Armstrong takes the side of atheists and agnostics against theists who think that being atheist or agnostic means per force that you are immoral.
He begins with the provocative question in Chapter One "Would You Marry an Atheist?" The answer is most people wouldn't. Furthermore, the prejudice against atheists and other non-believers is so great that an avowed atheist has no chance of being elected to high office in the United States. He notes that people in general fear atheists and discriminate against them simply because they are atheists, and that fear stems from the mistaken idea that atheists can't be moral. In the chapters that follow Sinnott-Armstrong argues with some force that religious people and theists in general may be more morally compromised than atheists. He cites studies that suggest as much.
Personally my experience with fundamentalist Christians and others who take the Bible literally is that their mental states are so compromised by the conflicting morality of the Bible that they practice a similar duplicity in their daily lives. If you've ever argued with a creationist you know what I mean. But Christians are not alone in their prejudices against non-believers. One finds the same antagonism in other religions, especially in Islam and indeed in the conservative expressions of most religions.
What Sinnot-Armstrong does not present here is the argument from psychology in which we see that people have neurological structures called "mirror neurons" that ape not just the behaviors of others but their mental states as well. Thus empathy and an identification with the plight of others is automatic and built into our nature in such a way that we are naturally moral animals who instinctively follow (most of us any way, for the most part) the edict of the Golden Rule which is to do unto others as you would have done unto you. We cannot help but feel that way unless of course we demonize others or make them our enemies or otherwise fear them.
Others have argued that our social nature as formed over the ages has molded us into moral beings who are capable of behaving in ways that reflect our understanding of what is right and wrong and guide us to behave in accordance with what is right. This surprisingly is a modern revelation and contrary to the spirit of the Bible in which humans are seen as fallen creatures who need God and the fear of punishment in order to behave morally. Supporting this belief in the news we constantly hear about people committing horrendous acts of hatred and violence, and of course nation states including our own have brought death and destruction on untold numbers of innocent people.
But these exceptions merely test the rule. Humans for the most part act morally because such behavior not only benefits them but other people as well, and is one of the reasons for the evolutionary success of the human race. For humans cooperation is what tames the jungle and molds the environment to our benefit, not blood thirsty competition.
Sinnott-Armstrong's tone is reasonable and reasoned and his argument thorough to the point of something like near exhaustion. He bends over backwards to be fair to both theists and atheists while insisting that these former antagonists can live in peace and harmony. I would say he is entirely convincing but I am part of the choir here, and so it would be better to hear what those skeptical of his thesis might think.
For those of you who are moderate in your religious views but not sure that you can trust non-believers this book might be an eye-opener.
(Note: Thirteen of my books are now available at Amazon including "The World Is Not as We Think It Is.")