The end of the trans-Atlantic slave trade in the British Empire is being commemorated this weekend, two hundred years after King George III granted royal assent to the Act for the Abolition of the Slave Trade. That slavery was (and remains) morally repugnant, and that its abolition was a good thing, is generally considered to be an incontestable truth.

But to play Devil’s advocate for a second, why is there such a fuss about slavery? What’s fundamentally wrong with it? In moral questions such as this, I defer to a greater authority.

It is full of interest. It has noble poetry in it; and some clever fables; and some blood-drenched history; and some good morals; and a wealth of obscenity; and upwards of a thousand lies.—Mark Twain (on the Bible)

The Bible is full of proscriptions of all kinds. It details the kinds of foods that God hates (prawns), the type of fabric that one shouldn’t wear (mixed fibres), and what should be done to gay men (kill them). God is very clear when He doesn’t like something, and there’s a lot of stuff that gets His sacrificial goat.

Paradoxically, slavery doesn’t make a blip on the deistic moral radar. Slavery is mentioned several times in the Bible, but nowhere is it countermanded. There are limits: for example, slave owners may not beat their property so badly that they die (at least, not so badly that they die immediately). But the concept of slavery per se is not portrayed as inherently wrong.

I haven’t deliberately misrepresented what the Bible says, but I am being slightly satirical. It does, I think, make the point that there are limits to the moral guidance that can be taken from ancient religious texts—and that right and wrong can exist without reference to scripture (or even in antithesis to it). Personally, I’ll always be suspicious of a book that places more weight on sartorial concerns than on human rights—and of anyone who believes that it holds all the answers.