The term “robot” and the idea of a robot rebellion were introduced by Karel Capek in Rossumovi Univerzální Roboti. “Robot” is derived from the Czech term for “forced labor” which was itself based on a term for slavery. Robots and slavery are thus linked in science-fiction. This leads to a philosophical question: can a machine be a slave? Sorting this matter out requires an adequate definition of slavery followed by determining whether the definition can fit a machine.

In simple terms, slavery is the ownership of a person by another person. While slavery is often seen in absolute terms (one is either enslaved or not), there are degrees of slavery in that the extent of ownership can vary. For example, a slave owner might grant their slaves some free time or allow them some limited autonomy. This is analogous to being ruled under a political authority in that there are degrees of being ruled and degrees of freedom under that rule.

Slavery is also often characterized in terms of forcing a person to engage in uncompensated labor. While this account does have some appeal, it is flawed. After all, it could be claimed that slaves are compensated by being provided with food, shelter and clothing. Slaves are sometimes even paid wages and there are cases in which slaves have purchased their own freedom using these wages. The Janissaries of the Ottoman Empire were slaves yet were paid and enjoyed a socioeconomic status above many of the free subjects of the empire.  As such, compelled unpaid labor is not the defining quality of slavery. However, it is intuitively plausible to regard compelled unpaid labor as a form of slavery in that the compeller purports to own the laborer’s time without consent or compensation.

Slaves are also often presented as powerless and abused, but this is not always the case. For example, the slave soldier Mamluks were treated as property that could be purchased, yet  enjoyed considerable status and power. The Janissaries, as noted above, also enjoyed considerable influence and power. There are free people who are powerless and routinely abused. Thus, being powerless and abused is neither necessary nor sufficient for slavery. As such, the defining characteristic of slavery is the claiming of ownership; that the slave is property.

Obviously, not all forms of ownership are slavery. My running shoes are not enslaved by me, nor is my smartphone. This is because shoes and smartphones lack the moral status required to be considered enslaved. The matter becomes more controversial when it comes to animals.

Most people accept that humans have the right to own animals. For example, a human who has a dog or cat is referred to as the pet’s owner. But there are people who take issue with the ownership of animals. While some philosophers, such as Kant and Descartes, regard animals as objects, other philosophers argue they have moral status. For example, some utilitarians accept that the capacity of animals to feel pleasure and pain grants them moral status. This is typically taken as a status that requires their suffering be considered rather than one that morally forbids their being owned. That is, it is seen as morally acceptable to own animals if they are treated well. There are even people who consider any ownership of animals to be wrong but their use of the term “slavery” for the ownership of animals seems more metaphorical than a considered philosophical position.

While I think that treating animals as property is morally wrong, I would not characterize the ownership of most animals as slavery. This is because most animals lack the status required to be enslaved. To use an analogy, denying animals religious freedom, the freedom of expression, the right to vote and so on does not oppress animals because they are not the sort of beings that can exercise these rights. This is not to say that animals cannot be wronged, just that their capabilities limit the wrongs that can be done to them. So, while an animal can be wronged by being cruelly confined, it cannot be wronged by denying it freedom of religion.

People, because of their capabilities, can be enslaved. This is because the claim of ownership over them is a denial of their rightful status. The problem is working out exactly what it is to be a person and this is something that philosophers have struggled with since the origin of the idea of persons. Fortunately, I do not need to provide such a definition when considering whether machines can be enslaved and can rely on an analogy to make my case.

While I believe that other humans are (usually) people, thanks to the problem of other minds I do not know that they are really people. Since I have no epistemic access to their (alleged) thoughts and feelings, I do not know if they have the qualities needed to be people or if they are just mindless automatons exhibiting an illusion of the personhood that I possess. Because of this, I must use an argument by analogy: these other beings act like I do, I am a person, so they are also people. To be consistent, I need to extend the same reasoning to beings that are not humans, which would include machines. After all, without cutting open the apparent humans I meet, I have no idea whether they are organic beings or machines. So, the mere appearance of being organic or mechanical is not relevant, I must judge by how the entity functions. For all I know, you are a machine. For all you know, I am a machine. Yet it seems reasonable to regard both of us as people.

While machines can engage in some person-like behavior now, they cannot yet pass this analogy test. That is, they cannot consistently exhibit the capacities exhibited by a known person, namely me. However, this does not mean that machines could never pass this test. That is, behave in ways that would be sufficient to be accepted as a person if it that behavior was done by an organic human.

A machine that could pass this test would merit being regarded as a person in the same way that humans passing this test merit this status. As such, if a human person can be enslaved, then a robot person could also be enslaved.

It is, of course, tempting to ask if a robot with such behavior would really be a person. The same question can be asked about humans, thanks to that problem of other minds.