"musket- of course the atheist can have morality without a law book , but what is his ultimate authority , and what is to stop that morality being variable?"

The point pete raises is an interesting one, as it can be difficult to for some to understand from where secular morality derives it's origin, integrity and foundation from if not handed down from a supreme being? In the modern world it might appear that secular society has abandoned wholesale any sense of moral direction as we slowly cower under the ever-increasing weight of the free market and it's anything goes approach to consumerism and disregard for any sort of common decency.

However, look closer and it becomes clear that there is a strong moral thread running through secular society, albeit one largely ignored by politicians, religious heads (often of the more fanatical ilk) and business leaders. It is present in the secular arts from painting to literature, in the way we look after our ill and vulnerable (the huge number of nameless, voiceless volunteers that give their time for others) and the concerns of the countless people debating on the internet every day.

Where did this moral code spring from? Many societies the world over have independently created moral codes that are very similar despite being separated by temporal and geographic location. This might indicate that as human beings we are predisposed towards certain traits, and these manifest themselves as laws such as "don't kill" or "don't steal". These universal laws are an expression of an innate morality that we all possess; religious texts of all creed are simply another manifestation of this instinct, and no religion can rightly claim to have been the wellspring for this wisdom.

There is no need to credit a supernatural being with creating a moral code which binds us as a species, as our ancestors originated it and we perpetuate it. The idea that anyone is less moral or has less moral authority because they are atheist is fundamentally wrong and rather patronising to say the least, as it suggests we are incapable, without help from a mythical third party, to create a basic and universal code of morality; however, we've done just that.

See, human beings are actually quite clever when they put their minds to it.