The words 'desire' and 'motivation' often appear in different kind of sentences for (what I assume is) grammatical reasons, but I have a really hard time separating them as concepts.
When we talk about desire or motivation it seems like we ultimately are talking about why we act; we are seeking some kind of explanation of our actions and without desire or motivation there will be no action. We act because we desire/are motivated by X.... What motivated you / what desires caused you to do that? Do you desire x / are you motivated by x?
It can be a physical (causal) explanation, e.g. the increase in dopamine drove me, it can be a design explanation, e.g. humans are 'designed to' pursue sugar, fat, sex etc, or it can be an intentional explanation, e.g. I work hard because I want money.
It might feel like an explanation is sometimes about desire and some times about motivation but are we really talking about any conceptual difference?
Please help me sort this out.
A side point (about MY definition of a value)
I understand that we can value something without being motivated by it. But a value to me is just a type of belief i.e. a belief about what we desire or should desire. Hopefully our values correspond to our desires; our values can influence our desires over time, but believing we value something does not automatically make us act accordingly; we have to make it emotional if we want something to drive us to action i.e. if we want something to motivate us / be a desire.