The alienation constraint on theories of well-being has been influentially expressed thus: 'what is intrinsically valuable for a person must have a connection with what he would find in some degree compelling or attractive …. It would be an intolerably alienated conception of someone’s good to imagine that it might fail in any such way to engage him' (Railton 1986: 9). Many agree this claim expresses something true, but there is little consensus on how exactly the constraint is to be (...) understood. Here, I clarify the sense in which the quote offers a basic constraint on theories of well-being—a constraint that should be adopted by (e.g.) hedonists, desire satisfactionists, and objective list theorists alike. This constraint focuses on affective engagement, or positive affective stances in connection with a proposed good. I show that the constraint explains a near-universal intuition, and rules out a number of well-known theories of well-being. (shrink)