Excellent last three posts. Plus this may be my nomination for quote of the week :
If desire is a pain, then per PD03 the limit of the magnitude of pleasure would include the removal of all desire. Is this what Epicurus had in mind? Then why would he describe natural and necessary desires? Does he say somewhere that gods have no desires?
That is an excellent observation. Also:
n other words, we've happened upon a very juicy topic
Yes. I cannot imagine that this topic was not a major one in antiquity. And did it not have a relatively easy explanation in which the very concept of desire is tainted with the negativity of being a pain then I cannot imagine that it would have been embraced by so many Romans.
I don't know if we have the original Greek of the phrase that Martin Ferguson Smith translates as "desires that outrun the limits fixed by nature," and it appears that the "outrun" may be Ferguson's own insertion, but after a couple hours of thought I still think that is a very useful way of looking at it. And if that is the case only the desires for things which are impossible by nature (eternal life, a personal relationship with a supernatural God, etc) are unnatural and intrinsically bad (painful because they are impossible by law of nature to fulfill) and merit to be called "roots of evil." From that perspective, even a desire for the latest iphone or a new Tesla is not "unnatural" even though the ancients never envisioned them.