referring to opossum, the other white meat on metamorphosism, the other blog.
most people who don't study law, don't live around people studying law or who do live around people studying law but don't respond to frequent corrections get ownership and possession mixed up. i did too, once- note the emphasis on did- and so probably did my latin teacher. the thing is, there's a very important difference here: possession is when i have it and ownership is when i own it. yeah, duh. sometimes i have it and own it- but sometimes i own it but someone else has it. those are the critical cases.
and sometimes people have something they can never own- maybe because they are not even entitled to own anything at all. such as sons (hence also the senatus consultum macedonianum so they wouldn't go around killing their fathers for mutuum debts), daughters and sometimes wives under the patria potestas of the pater familias. or such as slaves, who could be possessed and owned, just like things.
people like that could in some cases justify the pater familias' ownership/possession of something through some kind of act, they just couldn't do it for themselves. so, for example, a daughter whose dad is still alive could go to a roman hardware store and by a roman super drill. for a sales contract you only need the consensus on price and the thing you're buying. the super drill just won't belong to the daughter, but to the father, just like the money she's paying with won't belong to her. or if she goes to the roman drug store and buys ancient nail polish, guess who it's gonna belong to? (gee, and i sure hope these examples are correct. but i think you got what i meant.)
so what i'm getting at... if not even sons/daughters/sometimes wives could own anything, how could slaves? a thing can't own more than a person.
a slave owner could order one slave to serve another slave, of course. he could order a masseur to massage the teacher (greek slave). but he could also order him not to do it. that's the point- the pater familias/slave owner has that power. the owner also has more power/rights/claims than a possessor.
now, what would happen if the slave committed a delict? guess.