Dennis Prager, who is an American conservative political commentator, claims in this video* that you can't have morality without God.
I consider I am a moral person and most people who know me would agree. I am an atheist and I don't rely on the Bible or any other external source for my morality, so where does my morality come from? Is it merely a desire to conform to others' ideas of morality? I am not much of a conformist, as you can probably tell from the views expressed in my blog, so that doesn't seem likely.
I am moral because I think. Reason is the basis of my morality and in fact is the real source of all human morality, not religion. It is because we perceive the world through rational eyes that we have a morality at all.
Let us take the maxim, do unto others as you would have them do unto you. Jesus said this, right? Well, actually it predates Jesus and is common to many early human cultures including ancient Egypt, China and India. Thales said it in ancient Greece and Seneca in Rome. In fact, it is so universal it is known as the Golden Rule. Do we need religion to derive this principle? No, of course not. All we need is a rational mind that can conceive of the potential consequences to oneself of doing something awful to another. A little experience of life teaches us that human relations are based on reciprocity - if I act decently towards you, then it is more likely that you'll be decent to me. On the other hand, if you believe that I am evil because I don't believe in your god, the chances are that you won't treat me fairly no matter how well I treat you.
Few would dispute that the moral standards to which mankind generally adheres have improved over time. Many things that human beings accepted in the past as perfectly moral - such as slavery, the torture and killing of so-called heretics, the stoning of adulterers, etc. - have become morally repugnant in modern societies precisely because we are in an age of greater reason. In fact, all of these practices were not only condoned in the Judeo-Christian tradition, the Bible exhorts them.
Prager trots out the usual facile point that Adolf Hitler and Josef Stalin were atheists and were evil, as if this is proof of his argument. Actually, Hitler was a Catholic all his life and Stalin was a Russian Orthodox seminarian before he became a Communist, so they hardly support his case. He then goes on to say that it is no coincidence that it was Judeo-Christian societies that first abolished slavery. I would have thought anyone who looked to the Bible for moral guidance would realise how hypocritical it is to claim its teachings led to the end of slavery. And anyone with a sense of history wouldn't engage in a moral pissing contest in defence of religion.
I think Prager has the facts exactly reversed. If your morality comes from an external source, such as belief in a divine being who tells you what is moral and what isn't, then you have no intrinsic morality. In other words, you are amoral, if not sociopathic. Of course, even religious people use rational judgement to determine which of their faith's moral precepts they apply in their own lives. But only those who derive their morality from their own reasoned judgement can be said to be truly moral.
* H/T: Craig Biddle from The Objective Standard, who brought Prager's video to my attention, has responded in greater detail and more philosophical terms here.