If a time traveller dropped you off anywhere in the Roman EmpireLasting from 27BC to 476AD, the Roman Empire controlled regions around the Mediterranean in Europe, North Africa and Western Asia. in the year 50AD, slaves might be the first thing you notice. It is estimated that 10 to 20% of the population at that time was enslaved - between five and ten million people.

Being surrounded by people who are owned by others seems like a horrifying idea. But in fact, it is estimated that there are more slaves on the planet today than at any other point in history. And more than half of them are in wealthier countries.¹ Slaves are still everywhere: we just do not notice them.

Now, some are wondering why slavery is still so hard to get rid of.

For many people throughout history, the answer was simple: slavery is part of the human condition. Ancient Greek philosopher Aristotle thought that certain peoples were "natural slaves". They were incapable of living independently, and needed a master both to protect them and keep them in line.

Some believe Aristotle was actually using this idea to criticise slavery. By arguing that only some people were destined for slavery, he could also claim that most of those who were actually enslaved were not slaves by nature, and so should be freed.

But when Europeans began settling the Americans in the 16th and 17th Centuries, it became a useful pretext for enslaving the local populations. They declared that Native AmericansThe indigenous people of the Americas, who lived in the region before settlers from other places. were natural slaves who needed to be taught how to live properly by civilised Europeans.

Later thinkers denied that some peoples are slaves by nature, but still thought slavery was imprinted in the human mind. Philosopher Georg HegelA German philosopher who lived from 1770 to 1831. argued that human beings have a natural instinct to subjugateForcefully bring under control. each other.²

That is why some think slavery is simply impossible to get rid of. They say it has always been part and parcel of human societies.

But others believe this lets us off the hook. They point out that slavery throughout most of history, and in most of the world, meant something very different than it does today.

In China, for example, slaves were something closer to servants. They lived in their master's household and received an allowance. They regained their freedom when they reached a certain age.

Likewise, in West and Central Africa, the slaves that existed before European contact were considered subordinateA person under someone else's authority who is considered less important. members of their masters' families. They were frequently quite wealthy. Many male slaves had more wives than their masters did.

These systems were still unjust and repressivePreventing personal freedom. . But they did not involve the brutal exploitation of slave labour for economic purposes that characterises slavery today.³

This kind of slavery was a European invention. Europeans wanted to exploit the Americas for its natural resources, like silver and cotton. They forced Native Americans, and then Africans, to work, just to make themselves rich.⁴

So slavery as we understand it today, say the vast majority, is not part of the human condition. It is a colonial crime that still haunts the modern world.

Yes: Modern slaves mostly provide goods for western consumption: food for our tables, minerals for our smartphones, the clothes we wear. And richer countries are host to more than half of all slaves.

No: Modern slavery tends to come about from war, poverty and gender inequality. It is most prevalent in Africa and eastern Asia. Rich countries are certainly no worse than the rest.

Or... Rich countries have always been the worst offenders. They invented the modern system of slavery with their insatiableImpossible to satisfy. desire for resources, and that desire still fuels it today.