It's a matter of perspective, I think.
For example...
I own and use a very old Olympia SM 9 manual typewriter.
Certainly, I didn't design it, or gather up the raw materials to make it; I didn't build it, or transport it from the manufacturer, or sell it.
All I did was buy it.
Now, Dan Puls, the guy I bought the typewriter from, if asked 'What does Henry Quirk owe you?' would probably consult his receipts and conclude 'He owes me nuthin'...Quirk is paid in full.'
That is: Puls had a price, I paid it, now I owe him nuthin'...we transacted, each getting what we wanted.
The same chain of transaction extends, I think, all the way back to the designer of the typewriter...transactions wherein folks each got what he or she wanted, or contracted for, in exchange for what other folks wanted, or contracted for.
So where does 'the individual' (and definitions of 'individual') figure in to all this?
Well, that's kinda the point of my post: your quandary, Antonidas, isn't really about 'the individual' but about 'ownership'.
By way of the chain I describe above, I'm the owner of the typewriter (by way of market transaction).
Change the scenario, of course, and things play out differently. If, instead of market transaction, the above chain were governed by a form of communitarianism, then 'ownership' would leave out 'the individual' in favor of 'the community'.
That is: the market transaction favors the 'the one' while the communitarian scheme favors 'the many'.
Now, notions of what an individual 'is' do play into all of this, just not as the dominant conundrum.
In a market transaction, 'the individual' is assumed as the foundation, the start; in the communitarian scheme, 'the individual' is taken as component of the more important 'community'. In fact, some strains of communitarianism insist 'the individual' has no meaning outside the context of 'community'. That is, without the interaction of 'community', 'individual' ceases to be (as a market favoring guy, I think this is just crazy talk, but...*shrug*).
Again: I think your question is really more about 'ownership', not 'owner' (but, I could be wrong...

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