(Wondering if maybe we need to move some of these posts to a new thread, since this was originally a thread for Kungi.)
Agree with Kalosyni on that.
Additionally, I advocate getting away from the natural and "unnatural" descriptors. There are natural desires - those arising from nature - and those that are not natural arising from fruitless, void, groundless, empty beliefs. They are κεναί:
http://www.perseus.tufts.edu/hopper/text?do…57:entry=keno/s That's a much better description of what they are than unnatural. Unnatural implies they are somehow not human. They are unfortunately very human desires, but they're empty of substance and can never be satiated.
This is the exact same word Epicurus uses to name the "void" in "atoms and void." He's saying that there is literally nothing there to back up the desire. The void is the absence of atoms. It is the empty space within which the atoms move.