Pardon the delay.... Referring back to post #66, here's the Wikipedia link for desire fwiw:
https://en.wikipedia.org/wiki/Desire. I haven't had the chance to read the whole article but this excerpt from the beginning is to me pretty spot. I've underlined one sentence but the rest is also pertinent.
QuoteDesires are states of mind that are expressed by terms like "wanting", "wishing", "longing" or "craving". A great variety of features is commonly associated with desires. They are seen as propositional attitudes towards conceivable states of affairs. They aim to change the world by representing how the world should be, unlike beliefs, which aim to represent how the world actually is. Desires are closely related to agency: they motivate the agent to realize them. For this to be possible, a desire has to be combined with a belief about which action would realize it. Desires present their objects in a favorable light, as something that appears to be good. Their fulfillment is normally experienced as pleasurable in contrast to the negative experience of failing to do so. Conscious desires are usually accompanied by some form of emotional response. While many researchers roughly agree on these general features, there is significant disagreement about how to define desires, i.e. which of these features are essential and which ones are merely accidental. Action-based theories define desires as structures that incline us toward actions. Pleasure-based theories focus on the tendency of desires to cause pleasure when fulfilled. Value-based theories identify desires with attitudes toward values, like judging or having an appearance that something is good.
I wouldn't limit a desire to a mental concept, it could also be a physical or psychological craving.
I'm not very familiar with Nussbaum. Is she in the "absence of pain" camp? I can see how, if one was so inclined, they could mistakenly interpret Epicurus' categories of desires as tending toward asceticism. I look at them more along the lines of Maslow's hierarchy of needs, which maybe could be thought of as a positive, not negative, hedonic treadmill. More of a hedonic ladder.