great question. I was thinking about this too the other day; do we even own our own bodies? if we control not a single cellular process, how can we really be said to be in possession of our physical beings? and if we don't even own ourselves, it seems a fallacy to claim we can own anything at all. maybe this is why we are interested in controlling our minds, because the mind is the key to unlocking the secrets of the body and through it, manipulating with totality the external world - if you have COMPLETE mental exertion over your every physical reaction to the external environment, you could potentially effect EVERY action. total freedom, total power. it's an interesting thought.
you know, people say it's a waste of time to introspect, that if you really want to change things you have to affect the real world in some tangible way, but I think introspection is a way of cutting to the heart of the original problem, which is the inability to affect OURSELVES. once you know yourself, as in you can control yourself physically and mentality in every possible way, then manipulating the world becomes a simple thing. I wonder though, if it's a fool's game to even attempt such a thing - it presupposes separateness from the rest of the world, and in some fundamental ways, like the fact that we breathe air, we're intimately linked to all of it. oh, the real mystery is that we as human beings feel like distinct, independent individuals, when the reality seems anything but!