A conversation I had with David has been occasionally invading my mind over the months, and I feel it is time to resolve my confusion about it.
David Quinn wrote to me:
^ I just posted that again, because I would like people to read it. It's one of the most stimulating things I've ever read.If the boundary between myself and the rest of Nature was objectively real, then the needle wouldn't be able to pass through it and reach in under my skin. Similarly, I would not able to take advantage of the chair's mass and use it to support my body. It is precisely because boundaries are merely imaginary that interactions between things can take place at all - indeed, as easily as the interactions that occcur within things.
If we are to use differences in behaviour as the criteria for determining that boundaries are objectively real, then what of the differences within your own body? Take a bone out of your body and leave it sitting there on the table and it will just stay put, unmoving. Yet take some blood out and it will spill everywhere, staining everything in its path. Does this mean there is an objectively real boundary between the blood and bones inside your body?
If we were to take this line of thought to its logical conclusion, we would have to conclude that your entire body is nothing but a dense mass of objectively real boundaries. Yet even that's not true, for each of the components inside your body which have these objective boundaries can themselves be broken up into parts, with each of these parts having their own objective boundaries. Indeed, we can keep whittling it all down until there is nothing left at all, other than objective boundaries. The entire world would consist of nothing else but objective boundaries, each of them surrounding nothing at all.
But Ok David, what about sub atomic particles? Isn't it possible that there is some sub atomic particle out there that cannot be broken up?