Economics

Economists have modeled the circumstances under which slavery (and variants such as serfdom) appear and disappear. One observation is that slavery becomes more desirable for landowners where land is abundant but labour is scarce, such that rent is depressed and paid workers can demand high wages. If the opposite holds true, then it is more costly for landowners to guard the slaves than to employ paid workers who can demand only low wages because of the degree of competition. Thus, first slavery and then serfdom gradually decreased in Europe as the population grew. They were reintroduced in the Americas and in Russia as large areas of land with few inhabitants became available.Slavery is more common when the tasks are relatively simple and thus easy to supervise, such as large-scale monocrops such as sugarcane and cotton, in which output depended on economies of scale. This enables systems of labour, such as the gang system in the United States, to become prominent on large plantations where field hands toiled with factory-like precision. Then, each work gang was based on an internal division of labour that assigned every member of the gang to a task and made each worker's performance dependent on the actions of the others. The enslaved chopped out the weeds that surrounded the cotton plants as well as excess sprouts. Plow gangs followed behind, stirring the soil near the plants and tossing it back around the plants. Thus, the gang system worked like an assembly line.Since the 18th century, critics have argued that slavery retards technological advancement because the focus is on increasing the number of slaves doing simple tasks rather than upgrading their efficiency. For example, it is sometimes argued that, because of this narrow focus, technology in Greece – and later in Rome – was not applied to ease physical labour or improve manufacturing.

Scottish economist Adam Smith stated that free labour was economically better than slave labour, and that it was nearly impossible to end slavery in a free, democratic, or republican form of government since many of its legislators or political figures were slave owners, and would not punish themselves. He further stated that slaves would be better able to gain their freedom under centralized government, or a central authority like a king or church. Similar arguments appeared later in the works of Auguste Comte, especially given Smith's belief in the separation of powers, or what Comte called the "separation of the spiritual and the temporal" during the Middle Ages and the end of slavery, and Smith's criticism of masters, past and present. As Smith stated in the Lectures on Jurisprudence, "The great power of the clergy thus concurring with that of the king set the slaves at liberty. But it was absolutely necessary both that the authority of the king and of the clergy should be great. Where ever any one of these was wanting, slavery still continues..."

Even after slavery became a criminal offense, slave owners could get high returns. According to researcher Siddharth Kara, the profits generated worldwide by all forms of slavery in 2007 were $91.2 billion. That was second only to drug trafficking, in terms of global criminal enterprises. At the time the weighted average global sales price of a slave was estimated to be approximately $340, with a high of $1,895 for the average trafficked sex slave, and a low of $40 to $50 for debt bondage slaves in part of Asia and Africa. The weighted average annual profits generated by a slave in 2007 was $3,175, with a low of an average $950 for bonded labour and $29,210 for a trafficked sex slave. Approximately 40% of slave profits each year were generated by trafficked sex slaves, representing slightly more than 4% of the world's 29 million slaves.

Identification

Throughout history, slaves were clothed in a distinctive fashion, particularly with respect to the frequent lack of footwear, as they were rather commonly forced to go barefoot. This was partly for economic reasons, but also served as a distinguishing feature, especially in South Africa and South America. For example, the Cape Town slave code stated that "Slaves must go barefoot and must carry passes." It also puts slaves at a physical disadvantage because of the lack of protection against environmental conditions and in confrontations, thereby making it more difficult to escape or to rebel against their owners.

This was the case in the majority of states. Most images from the respective historical period suggest that slaves were barefoot. Brother Riemer stated, "[the slaves] are, even in their most beautiful suit, obliged to go barefoot. Slaves were forbidden to wear shoes. This was a prime mark of distinction between the free and the bonded and no exceptions were permitted."According to the Bible, shoes have been considered badges of freedom since antiquity: "But the father said to his servants, Bring forth the best robe, and put [it] on him; and put a ring on his hand, and shoes on [his] feet" (Luke 15:22). This aspect can be viewed as an informal law in areas where slavery existed as any person sighted barefoot in public was assumed to be a slave.

In certain societies this rule continues. The Tuareg still unofficially practice slavery and force their slaves to remain barefoot.Another widespread practice was branding, either to explicitly mark them as property or as punishment.

Legal rights

Depending upon the era and the country, slaves sometimes had a limited set of legal rights. For example, in the Province of New York, people who deliberately killed slaves were punishable under a 1686 statute. And, as already mentioned, certain legal rights attached to the nobi in Korea, to enslaved people in various African societies, and to black female slaves in the French colony of Louisiana. Giving slaves legal rights has sometimes been a matter of morality, but also sometimes a matter of self-interest. For example, in ancient Athens, protecting slaves from mistreatment simultaneously protected people who might be mistaken for slaves, and giving slaves limited property rights incentivized slaves to work harder to get more property. In the southern United States prior to the extirpation of slavery in 1865, a proslavery legal treatise reported that slaves accused of crimes typically had a legal right to counsel, freedom from double jeopardy, a right to trial by jury in graver cases, and the right to grand jury indictment, but they lacked many other rights such as white adults’ ability to control their own lives.

History

Some scholars differentiate ancient forms of slavery from the largely race-based slavery. The first type of slavery, sometimes called "just title servitude", was inflicted on prisoners of war, debtors, and other vulnerable people. Race-based slavery grew to immense proportions starting in the 14th century. It was argued even by some contemporary writers to be intrinsically immoral.

Early history

Slavery predates written records and has existed in many cultures. Slavery is rare among hunter-gatherer populations because it requires economic surpluses and a substantial population density. Thus, although it has existed among unusually resource-rich hunter gatherers, such as the American Indian peoples of the salmon-rich rivers of the Pacific Northwest coast, slavery became widespread only with the invention of agriculture during the Neolithic Revolution about 11,000 years ago.In the earliest known records, slavery is treated as an established institution. The Code of Hammurabi (c. 1760 BC), for example, prescribed death for anyone who helped a slave escape or who sheltered a fugitive. The Bible mentions slavery as an established institution. Slavery was practiced in almost every ancient civilization. Such institutions included debt bondage, punishment for crime, the enslavement of prisoners of war, child abandonment, and the enslavement of slaves' offspring.

Classical antiquity

Africa

Slavery existed in Pharaonic Egypt, but studying it is complicated by terminology used by the Egyptians to refer to different classes of servitude over the course of history. Interpretation of the textual evidence of classes of slaves in ancient Egypt has been difficult to differentiate by word usage alone. The three apparent types of enslavement in Ancient Egypt: chattel slavery, bonded labour, and forced labour.