Notes during editing:
I set up a separate thread for the issue of Happiness not requiring absolute absence of pain, and I'm going to name this episode something to the effect that Epicurus does not consider Happiness to be a binary state (where the only two options are happiness and unhappiness).
That raises something that Joshua points out, however: Epicurus does treat pain and pleasure as a binary state - that you are either feeling one or the other but not both at the same time and not an in-between state.
So we'll want to discuss: what's the difference between "happiness / unhappiness" and "pleasure/pain?"