Let's share our perspectives on the differences between the Epicurean and Cyrenaic understandings of pleasure.
I believe that that the Epicurean conception and definition of pleasure was formulated to combat the Cyrenaic conception and definition of pleasure and that the perceived oddity of Epicurus' understanding of the term pleasure (as we see in Cicero who expresses bewilderment at how Epicurus defines it) is best understood in the context of Epicurus trying to separate his own position on pleasure from the position of the Cyrenaics.
For Epicurus the ultimate pleasure ideal is a continuous mental state that we have to fully immerse ourselves in and then perpetually remain in it.
For Cyreanics the ideal of pleasure is an active pursuit that resembles going on a hunt and it's sensually oriented. For them the ideal condition is having access to an endless cake of pleasure where you enjoy one piece at a time till you are satiated and when the satiation goes away you come back for more slices.
The ideal life for the Cyrenaics consists in successfully chasing concrete experiences that cause direct pleasure.
For the Epicureans the ideal life consists in doing what's necessary to achieve a permanent state of pleasure and not allowing yourself to stray from it.
So that's why Epicurus put the focus on the pleasures of the soul as the secure guide to a fulfilled life. Epicurean pleasures are permanent while Cyrenaic pleasures oscillate between fulfillment and satiation.
Of course, Epicurus doesn't reject the sensual pleasures that Cyrenaics favored but for him they serve a secondary function as ornaments and auxiliaries to pleasure and do not constitute the primary focus of the whole pleasure enterprise.
Do we have evidence that the Epicurean ideal of stative and permanent pleasure is attainable? Plenty. One example is the Piraha tribe. Daniel Everett described the Piraha as living in a state of permanent happiness and joy. Another researcher remarked that if we tried to measure the amount of time in a day they spend laughing and smiling they would probably come out as the happiest people on earth.
In the video below a Piraha man is talking in his language. And you can definitely see that there's a permanent smile and a permanent glow of happiness and serenity painted on his face. This guy can safely be said to have attained ataraxia. And he is not some unusual person. The same thing has been observed to be a general feature of his people.
Do we have to live in the jungle to reach a comparable state of bliss? Of course not. But certain aspects of our social life would doubtless have to be seriously modified to rival this person in sheer eudaimonia.
There is another thing about the Piraha that reflects Epicurus' insistance on extreme empiricism.
The Piraha believe everything they see to be true and for this reason – Everett says – have a lot of trouble distinguishing fact from fiction. The Piraha are so extreme in their empiricist approach to life that they simply refuse to consider any claim unless somebody they know has been a direct eyewitness to it and their language always marks for evidentiality. Their extreme empiricism also shows itself in the absence of abstract notions like numbers and counting and the absence of anything we can associate with religion like rituals or a creation story. They do believe in spirits that talk to people but only because they see them in what we can only take to be hallucinations.
The extreme empiricism of this supremely happy people (challenges and all) got me thinking that Epicurus was really up to something when he recommended exactly this approach to epistemology. The Piraha rejection of mathematical abstractions also reminded me of Epicurus' rejection of geometry.