Online Personally, I doubt that the denial of a neutral state is of as much practical significance as it is of "logical" significance in debating with Plato on the nature of pleasure as the greatest good.
I'm not sure about that. It could have been (and I admittedly need to return to the texts) connected with his observation in PD2 that all feeling is based on consciousness and if you were neutral that might imply not having any sensation. If you're alive you're either feeling pleasure or pain
Since we're (that is I ) seem to have taken us down a modern science research track on this thread, here's an interesting article after skimming it. Putting it here for future reference:
This is actually even more interesting because the intersection of the axes could be considered a neutral state, but if all states in this model must occur on the circle itself then there is no neutral state.
Thanks for that, Godfrey ! I think you're right. The only truly "neutral" state would be at the intersection of the two axes which can't actually exist if the affect exists in the circle. So Epicurus was "right" in a sense that there is no neutral state. You're either feeling pleasure or pain.
Quote from NikolskyThe two parts of the division about which Epicurus is speaking - απονια and αταραξια, on the one hand, and χαρα and ευφροσύνη, on the other - are not separate, mutually exclusive types of pleasures. According to Plutarch, who examines these concepts in Chapters 7 and 8 of his dialogue A Pleasant Life Impossible (109la-1092d), the states of painlessness and tranquillity invariably bring about joy. This essential connection between the concepts mentioned by Epicurus compels us to view Epicurus' passage quoted by Diogenes Laertius not as a classification of pleasures but rather as a definition of two coexistent aspects of any pleasure: its passive aspect, i.e., a certain state of the body or the mind, and its active aspect manifesting itself in an emotional response of the soul.
I'm skimming Nikolsky and came across this passage. Is it me or do the "two coexistent aspects" sound somewhat like the arousal axis on the circumplex? I need to go back and read that more closely.
Is there some reason for the circle rather than just the two axes?
It's the natural curve from high pleasure valence/low arousal to low pleasure/high arousal and right around.
Think of it as plotting points like:
X0, Y10
X1, Y9
X2, Y8
etc.
Obviousky I didn't say it very well because I thought I was trying exactly what you said
LOL! Well, there's how schisms get started! 
Why I think we are both talking about is walking and chewing gum at the same time -. We can experience more than one thing at once, with one hand feeling pleasure and the other feeling pain (though there are probably better examples).
Okay, I might be able to go with that. And, in lights of that then, I might be able to see your "ice cream in prison" metaphor. I was using the flavors of ice cream to demonstrate the "flavors" of pleasure: euphoria, joy, excitement, orgasmic, etc. You, I think, were using the ice cream to demonstrate that we can experience pleasure tinged to various degrees with pain. Correct me if I'm mischaracterizing your position. If that's it, I can acknowledge that. Our goal, if you will, is to try to increase the pleasure side of that ledger and minimize the pain side.
The tricky thing is that Epicurus recognized that not feeling pain in itself is a pleasurable feeling. Which brings me back to the ideas of balance and homoeostasis as pleasure. This seems to me to be Epicurus's "health of the body and serenity of the mind."
I don't think those PD's say what you're trying to make them say.
To my interpretation, PD12 and its ἀκεραίους τὰς ἡδονὰς (akeraious tas hedonas) "pure pleasures" are simply pleasures experienced without the taint of fear. I think the Epicurus Wiki translation does a good of highlighting this: http://wiki.epicurism.info/Principal_Doctrine_12/
QuoteThus, concludes Epicurus, the study of nature is necessary, for without an understanding of nature, it is quite impossible to enjoy one's pleasures unsullied by fear.
It's not the pleasures themselves that are "pure" it is the experience of pleasure that is pure. Without understanding nature and eliminating the fear of the gods, you can't experience pleasure without that nagging in the back of your mind of fear of the supernatural gods raining down punishments on your heads or being scared of lightning, thunder, earthquakes, etc. as some form of divine retribution.
And PD14 doesn't talk about "pure pleasures" but the "truest safety" from other people. So, there's no purity of pleasure problem there. The "surest safety" is simply that which is free from anxiety or fear of harm from other people.
That's all I have time for now (sorry), but I have more thoughts on your other points. "Film at 11" 
I don't would say the better analogy would be like eating ice cream in an ice cream parlor vs in a jail cell vs in a war zone vs in a hospital etc.
I'm not sure I agree with your analogy. Pleasure and pain are the most basic categories of feelings. I think that's why Epicurus can say "the feelings are two." But within those two, if you drill down, you have joy, excitement, sorrow, calmness, boredom, anxiety, etc. All are words or divisions we give to degrees or types of pleasure and pain. Pleasure is "ice cream". Strawberry, Rocky Road, and vanilla are joy, excitement, and anticipation.
I have more thoughts on your other points. I'll get that posted asap.
On Lisa Feldman Barrett's affect:
This is an older paper (and WAY into the weeds!) but I thought this quote was helpful:
QuoteThe term “core affect” has been recently introduced to refer to a basic, psychologically primitive state that can be described by two psychological properties: hedonic valence (pleasure/displeasure) and arousal (activation/sleepy).
This is the idea of the "affective circumplex" (the name for the 2d grid).
they are manners of experiencing pleasure
Like different flavors of ice cream?
Stable
and "without pain" and "without disturbance" I think are adverbs
ataraxia and aponia are nouns not adverbs. They are states, best translated into English by words ending in -ness, e.g., painlessness or calmness.
In looking (briefly) at some of the translations of katastematic, it seems to me that balanced or steady would be a better definition than "static." It comes from καθιστημι according to LSJ with connotations like restore, return, set in order, etc. So it's not a static state, it's a return to order (ataraxia and aponia) after the "excitement" of euphrosyne and khara.
What is the definition you're working with for 'homeostasis"
Basically, the body's systems in equilibrium.
If I remember correctly, a common Epicurean theme is sailing calm waters and safe harbors. Ataraxia itself has an "untroubled waters" connotation.
I find it intriguing that homeostasis and katastematic have the same roots in light of my question above:
Is homeostasis similar to Epicurus's concepts of ataraxia and aponia?
Reason is by no means its own reward, and it should not be worshiped as a goal or an end in itself,
But pleasure IS its own reward and is a goal in itself... which is what makes it the greatest good. Couldn't resist poking that bear again
Here's another article from the popular magazine Psychology Today. I found the last section intriguing in light of the Stoic tendency/practice of enduring pain to "overcome" it.
I'm also wondering if the usual translations of choice and avoidance is more due to modern nomenclature than Epicurus's original wording which was more choose and flee from.
An intriguing episode of NPR's Fresh Air with Dr. Anna Lembke.
I was initially pulled in by the pleasure and pain in the title and found some very interesting points for discussion here on the forum.
Dr. Lembke clearly states evolution has given us pleasure and pain to guide us in what to pursue and what to avoid. I found her choice of words interesting.
Is homeostasis similar to Epicurus's concepts of ataraxia and aponia? Did Dr. Lisa Feldman Barrett also talk about homeostasis?
I had never heard the term anhedonia "absence of joy."
Lembke's "Radical honesty" sounds a lot like Epicurean frank speech.
Side note: One aspect of Epicureanism I find intriguing is that it deals with a real, physiological phenomenon - pleasure and pain - that can be researched. Stoics don't have that. Platonists don't have that. I don't know if that's a strength or not (I'm inclined to think it is), but the fact that I can find science videos and podcasts relevant to the philosophy is interesting.
Thoughts?
Lucretius V.526-33
This only do I show, and follow on
To assign unto the motions of the stars
Even several causes which 'tis possible
Exist throughout the universal All;
Of which yet one must be the cause even here
Which maketh motion for our constellations.
Yet to decide which one of them it be
Is not the least the business of a man
Advancing step by cautious step, as I.
http://wiki.epicurism.info/Philodemus/
According to this, there are at least 3 books in On Signs and Methods of Inference contained in PHerc 1065.
It also lists On Methods of Inference (1978)
Is Delacy a full translation of PHerc 1065?
I'd suggest we take a closer look at the paper by Manetti.
PS According to chapter 2 of Delacy, his work does appear to be a translation of PHerc 1065. If you read that chapter, it also seems to allude to the On Signs alternative title.
The major advantage of calling these people "Megarians" is that in "American" that sounds like they are some evil nation from some faraway planet!
Well, probably to an Athenian, those people in Megara were from some evil nation when it came to their philosophical school.
