What is it to be me? Is my me-ness in my head? Is my me-ness in my environment? If it's both, how do they relate? What is 'mine' about my life? My head? My little finger?
What about "my phone"? computer? blog? tweet? (etc...) For some of these things (like my blog) I might say "I did it, therefore it is mine". There are a number of things to say about this in particular. Firstly, it clearly is related to the issue of 'intellectual property'. Secondly, it clearly is an example of Locke's 'labour mixing' theory of property. To that, we might ask whether the labour-mixing theory is really any good as a theory of property - and, personally, I find it rather unsatisfactory.
Rather than labour mixing, I think my-ness (property) is constituted by sensual relations with things around us and communications with others. What is 'mine' is that in the environment which serves a purpose in the sensual relationship I have with it, to contribute to the mechanism of my personal viability. Seeing property like this means that we can begin to appreciate how the changes we are experiencing in the world are impacting on our human nature - on our very sense of 'identity'.
If individual identity is constituted by 'property relations' then this means that the manipulations of capital and matter are manipulations of personal identity. And identity is probably the most significant causal factor in conflict, as Armatya Sen has recently highlighted. The evidence for identity being constituted by sensual 'property relations' I think is compelling. Only this perspective allows us to consider the impact of grief on the death of a loved one: "part of me died..". And even the 'first scratch on the new car' can instil feelings of 'incompleteness' and regret in our identity. Justice and crime also relate to these feelings of identity: to have property stolen is felt as an affront to identity. And as Erich Fromm has pointed out, individuals have property relations to ideas too. And, again, when our cherished ideas are challenged, we similarly feel an assault on who we are.
Moreover, I think that such transient insecurities of identity lie at the heart of economic processes. Property relations pass from one thing to another: the mobile phone gradually gets battered and the battery fails; a new 'compensatory' product appears and we re-establish our identity with that, discarding what we had before.
Education may be a process of building identity. As parents, we begin by encouraging our children to be more independent: from being in the playground and helping our child see if "you can come down the slide on your own" to trusting children to go to the shops on their own, much of our parenting would appear to be a process of scaffolding the establishment of property relations with the world. In higher education, I think this process continues, but it is not the slide in the playground, but the sensual relations with the great and the good, the works of art, the canon, the library. In this sense, even skills become sensual relations, like the hard-won technique of the artist or musician.
But what I don't think is that any of this actually 'exists' in individual brains. I suspect instead that the brain regulates a 'game' that is played with those things with which we have sensual property relations. But that isn't my idea. I think Kant got there first in the Critique of Judgement...