I just received an assignment from a client about the U.K. Modern Slavery Act, which requires companies trading in the U.K. to ensure there's no slavery or human trafficking in their supply chains.

This got me wondering about the whole question of slavery. People have been enslaved throughout history in most cultures, and it still goes on. Yet we all agree that it's wrong to buy and sell people. What's the source of our moral outrage? It's certainly not the Bible. Slavery is accepted and encouraged in many books of the Bible. Abraham had slaves, including a sex slave who bore him a son called Ishmael. St. Paul returned an escaped slave to his "owner." I'm not sure what the Koran says about slavery, but Muslims have certainly been major slavers.

So if religion provides no moral basis for condemning slavery, what about economics? Early economists in the 18th and 19th century condemned slavery as economically inefficient. A slave is likely to be a poor worker. He will never be a consumer. And slavery also takes away the incentive to modernize and mechanize by turning people into farm machinery. This view caused Thomas Carlyle to call economics the "dismal science" in an essay defending slavery in the West Indies. He actually claimed that conditions on Atlantic slaving vessels were not all that bad.

So where do I stand as an atheist? I want my children and grandchildren to have opportunities, dreams, adventures. I would be outraged if anyone tried to limit their potential or claim ownership over them. My sense of empathy reminds me that everyone is someone's child or grandchild, so I feel sorrow when I hear about people who were denied all the good things I want for my family. That is why I find slavery morally repugant.

What do others think?