Strike, dear mistress, and cure his heart

Frankfurt, in On Caring, shortly after announcing that he isn't certain why volitional constraint "should be so precious to us", gives a description of just that (that features, obviously, in other essays and lectures of his), to wit:

Suppose a man tells a woman that his love for her is the only thing that makes his life worthwhile … The fact that loving her is so important to him will not strike her as implying that he does not actually love her at all or that his love for her is tainted by self-regarding concerns. The apparent conflic between selflessness and self-interest disappears once it is understood that what serves the self-interest of the lover is, precisely, his selflessness. The benefit of loving accrues to him only if he he is genuinely selfless. He fulfills his own need only because in loving he forgets himself.

(The same argument comes up practically identically phrased in The Reasons of Love, is alluded to in Autonomy, Necessity and Love, and is a case of the argument in On the Usefulness of Final Ends and maybe On the Necessity of Ideals.) There are supposed to be lots of good things about love on Frankfurt's account, but the principle service it renders those in its grip is that it settles questions of what to do.  Frankfurt will go so far as to say that the totality of what a person cares about, combined with the order of rank of those cares, answers for him the question of how to live—either because he thinks that the cares and their ordering suffice to guide action all the way down, or because he thinks that, should any gaps remain, there's no way to fill them anyway.  Caring, and loving specifically, are willing captivations (thus not enslavements, as to passions—and willing in the double sense of being endorsed and being internal to the will) that circumscribe the range of reasons one will be able to consider, and not able not to consider; they proscribe some, and prescribe other, actions, in a way internal to the process of any possible deliberation.  This comes about because the lover takes himself to be subordinated to his beloved (or its interests), and it is only because of this subordination, moreover, that loving is important to us for its own sake.

All of which makes it rather striking that, when Jonathan Lear wants, as so many do, to get Frankfurt to admit some carings/lovings shouldn't be considered authoritative for the agent, because they're immoral or even outright evil, he chooses (this is in his contribution to Contours of Agency) the example of a slave's love for his master.  But this—much more than Frankfurt's own favored example of a parent's love for h/h children—is the paradigm case of what Frankfurt describes, because it requires the minimum of creativity on the part of the agent. There is no ambiguity as to how to serve the interests of the beloved, when one is literally enthralled: you do what, when, and as you're told. This language of self-abnegation, of self-forgetfulness, captivation and subordination, it isn't just decorative.