Since Aristotle on natural slavery is the philosophy twitter topic of the day, I thought I'd say something about his actual argument (and some of the reasons why it's wrong). I take his argument to be (roughly) this: 1/

1) Some people are, by nature, constituted in such a way that they can't be excellent practical reasoners.
2) If someone can't exercise practical reason well it would be better for them to do what a practically wise person tells them to do than to rely on their own faculties 2/

3) To offload one's practical reasoning to another as (2) describes is to be a slave to that other person.
4) So, being a slave is, for some, good. (It's better to have someone else rule you than have your body (and the passions) rule your soul (and reason). 3/

There's a lot wrong with this. But I just want to point out two errors. First, (3) is false. Being a slave, a living instrument, doesn't consist is offloading one's practical reasoning in this way. It involves one's actions no longer being directed toward one's own end/good. 4/

That's what makes one an "instrument". A slave's actions no longer occur for the sake of their own end/good but are instrumental for bringing about the end/good of someone else. Nothing Aris. says justifies subjugation to that kind of rule. Aris. takes this analogy seriously. 5/

As a good hammer facilitates the craftsman attaining their ends, so a good slave facilitates the master attaining theirs. Enslavement can't be good for the slave qua human being, since enslavement undermines consideration of their own ends as human beings altogether. 6/

Second, (2) is false. The "modern" charge against Aristotle shouldn't be 'racism' or 'colonialism' (he argues against both as grounds for slavery). If anything, it's a pernicious kind of ablism. The idea that it's sometimes better to follow the sage advice of the wise is 7/

transformed into the view that individuals who don't meet some threshold of "proper functioning" would be better off giving up on living rational human lives altogether. If there is something repugnant in what Aristotle says, I think it's this. 8/

Though I study Aristotle, his Politics isn't my area of expertise. So I'm sure specialists will disagree with much of this thread. But I think there's value in seeing why bad arguments are bad. This is one reading of why this one is. 9/

Thanks to @AgnesCallard for prompting these thoughts. 10/10