Greenspan's principal research interests lie in
moral philosophy,
moral psychology, and the
philosophy of action. Her work has ranged among several interconnected subtopics, as follows: •
Deontic logic: Greenspan's Ph.D. dissertation and her first published article dealt with the logic of ought-judgments, arguing that "oughts" are "time-bound" and that wide-scope conditional ought-judgments allow for detachment only when their antecedents are no longer avoidable. •
Free will and
moral responsibility: Greenspan's second major article and ongoing work argues that freedom depends on the difficulty of doing otherwise, rather than simply ability, and hence admits of degrees. Greenspan's developed view also distinguishes between freedom and responsibility, arguing that the compatibility of responsibility with free will does not imply a similar compatibilist view of freedom. Greenspan has applied some of her work on these subjects to questions arising from the U.S. Genome Project and to the issue of the responsibility of psychopaths. •
Emotion: Greenspan next began a long-running project on the rational and moral role of emotion with the publication of an article defending the rationality of ambivalent emotions in an argument designed to cast doubt on attempts by several contemporary philosophers to equate emotions with evaluative judgments or beliefs. Her first book argues instead that emotions amount to feelings with an evaluative intentional content short of belief that makes them both susceptible to a distinctive kind of rational assessment and important in a distinctive way to rational and moral motivation, paradoxically serving as a counterforce to weakness of will. A second book and some later essays simplify this account, defend it against some common objections, and apply it to further issues, as outlined below. •
Moral dilemmas: In an essay and in her second book Greenspan argues for the coherency of irresolvable moral dilemmas, cases in which all alternatives are forbidden. She sees dilemmas as a result of the need to establish the motivational force of morality by forging a connection in childhood between emotions and rules simple enough to be learned at that early stage. •
Metaethics: Greenspan defends what she calls a "social artifact" version of
moral realism, in which morality is invented, yet "real" (in the sense of mind-independent) insofar as it reflects the requisites of life in a viable social group. She sees emotion as essential to the motivational force of moral judgments in general terms, though not necessarily on each occasion of use or for every agent. She thus departs from contemporary "internalist" understandings of moral meaning that deny the possibility of understanding a moral judgment without being motivated by it. •
Practical reasons and
rationality: Greenspan argues that emotions play a significant role in rational thought, as noted. In recent work she gives an independent account of practical reasons as registering or responding to criticism. The account allows for the rational permissibility in certain cases of action against one's strongest reason and is brought to bear on issues including the rationality of "satisficing" (choosing less than the best) and the notion of "imperfect" obligation (an obligation that leaves room for options). ==Selected works==