How could the great philosopher of human flourishing endorse slavery?

Aristotle (384-322 BCE) was the great philosopher of human flourishing. He argued that although health, wealth, honour, pleasure etc. may be sought for themselves, we choose them also for the sake of living well. Living well involves making use of the vital functions that make us human. Many of the vital functions of humans, including nutrition, reproduction and movement, are the same as those of other animals. However, humans also have the capacity to use reason to guide themselves and exercise appropriate moderation in their behaviour. Parents and fellow citizens may help us to acquire good habits, but we are individually responsible for exercising the practical wisdom that we require to flourish.

It would be reasonable to expect that a person who held such views would be opposed to slavery on the grounds that slaves can only use reason to guide their actions within the limits imposed by their owners. So, how could Aristotle endorse slavery?

Julia Annas explains in The Morality of Happiness that Aristotle saw slavery to be natural. His appeal to nature has two aspects. The first is his claim that slavery has a natural basis in differences between types of people. According to Aristotle, there are “natural slaves” whose “state is such that their function is the use of their body, and this is the best they can do”. On that basis he argues that “it is better for them to be ruled”. He also suggests that the benefits owners obtain from use of slaves “differs only a little” from those obtained from use of domesticated animals. Aristotle saw the relationship of subordination between owner and slave as an example of a general pattern, also encompassing the relations between men and women (p 152).

The second aspect of Aristotle’s appeal to nature was based on his observation that slavery was widespread and should therefore be considered natural.  (p 153).

Julia Annas suggests that Aristotle’s defence of slavery fails even in terms of his own view of what is natural. Aristotle distinguishes between natural behaviour, governed by internal sources of change, and forced behaviour, brought about by external factors that overrule the internal sources of change. Even if we were to accept Aristotle’s claim that some people are natural slaves, that cannot explain the functioning of actual slavery which is based on the use of force.  Again, Aristotle’s observation that slavery was a “near universal social institution” did not justify his inference that it is natural in the sense of not resting on force. Annas comments:

“The usual may be natural with plants and animals, but the complexity of human nature allows the usual to be something that is forcibly repressed, unjust and in every way frustrating to normal human capacities” (p 155).

How could Aristotle not see this? Perhaps he perceived that some people are natural slaves because he couldn’t imagine the slaves he knew as free citizens. Many of us have a somewhat similar problem today is assessing the potential of individuals to accept more responsibility than they have at present. There seems to be a common cognitive bias that leads us to identify people with their current roles. We don’t know what people are capable of until we see them in a different role.

Aristotle’s perception that it was natural to make slaves of defeated enemies can possibly be explained as the biased perception of a slave owner, but his loose definition of circumstances in which external force is involved left him scope to take a biased view. He was able to disregard the use of force at the heart of the system of conquest and slavery by identifying the whole system as a natural system.

Similarly, Aristotle’s loose definition of circumstances in which external force is involved enabled him to condemn the profit motive and the market economy. In this instance he identified the natural system as the primitive system of directly producing what meets one’s needs, and only using exchange as much as required to satisfy unmet needs and get rid of unusable surplus. That enabled him to identify the market economy as an external force that disrupted a natural system.

Aristotle’s view of what is natural would have been less prone to bias if it had been based on the natural rights of individuals, and hence the naturalness of mutually beneficial voluntary cooperation and exchange among individuals. That would have made it much more difficult for him to condone any use of force (coercion) that constrains individual flourishing.

However, we shouldn’t judge Aristotle too harshly for his wobbly views about what is natural. It is worth remembering, that a more coherent view of natural law didn’t prevent eminent philosophers who lived much later from also endorsing slavery. For example, Thomas Aquinas, who lived over 1500 years after Aristotle, also endorsed slavery despite holding the view that the first precept of the natural law is to do good and avoid evil.

A question worth exploring further is the extent to which Aristotle’s views on the potential for individual human flourishing played a role in the eventual recognition of the natural rights of individuals, via Aquinas’ endorsement of those views in his natural law theory of morality.