I haven't had a chance to read this one yet, but looks directly on point with our discussion here in this forum:
Cicero obfuscating and arguing out of both sides of his mouth?! Say it ain’t so! 
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Although the main matter here may have to do with mortality, the following struck me:
“‘Cicero’ conflates both argumentative strategies. On the one hand, he shows (i) that also according to non-virtue single-good schools, the goods required for happiness are available even under adverse circumstances, while conditions regarded as bad are no bads or at least not so bad that it would be impossible to obtain the goods constitutive of happiness. On the other hand, (ii) he attributes to virtue an instrumental function for guaranteeing happiness.
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“All types of real non-virtue goods are sufficiently available for a person to be happy, and there is no reason to suffer from apparent bads that one can despise and disregard (strategy i). However, a person also needs the ability to assess goods and bads correctly, must assume the right attitude toward them and make the right choices. This ability is virtue, understood here as a mind educated to assess correctly what is good or bad so that it does not value what is worthless or fear what is harmless (strategy ii).”
As I recall, the primary practical (instrumental) virtue for the Stoic Epictetus was what we today would call agency: exercising our ability to choose among options.
It seems to me that this virtue is precisely what Epicurus emphasizes in our practical ability to choose among (1) the three categories of desires, and (2) pleasures that may lead to pain and pains that, if endured, lead to greater pleasure.
Possession of this virtue itself does not guarantee happiness (eudaimonia – with due recognition of problematic translation), but only its astute application. Virtue cannot be the only thing necessary for happiness (let alone, as the author mentions earlier, being happiness!) – but rather its instrumental application toward what is happiness: pleasure.
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There, at bottom, seems to be a kind of vicious circularity in the Stoic notion of virtue being the sole necessary and sufficient “good” for eudaimonia – let alone constituting eudaimonia. Virtue is either instrumental or not. Cicero seems to want it both ways.
