Imaginability, Possibility, and the Puzzle of Imaginative Resistance

I Introduction

It is standard practice in philosophical inquiry to test a general thesis (of the form 'F iff G' or 'F only if G') by attempting to construct a counterexample to it. If we can imagine or conceive of¹an F that isn't a G, then we have evidence that there could be an F that isn't a G — and thus evidence against the thesis in question; if not, then the thesis is (at least temporarily) secure. Or so it is standardly claimed.

But there is increasing skepticism about how seriously to take what we can imagine or conceive as evidence for (or against) a priori philosophical theses, given the many historical examples of now-questionable theses that once seemed impossible to doubt — and also the recent experimental research suggesting that our verdicts on Gettier cases, trolley cases, and the scenarios depicted in other familiar thought-experiments may be affected by cultural, situational, and other adventitious factors.² There are further worries concerning a posteriori propositions such as 'Water is H2O,' or 'Hesperus is Phosphorus.' It seems easy to conceive or imagine counterexamples to these theses, even though they are commonly regarded to be necessary truths — and though Kripke and others argue that we can reconstrue those alleged counterexamples as mere 'look-alike' scenarios that are genuinely possible, there is dispute about what this strategy involves, and considerable skepticism about its efficacy. Indeed, many materialists take Kripke's contention that we can imagine, but cannot reconstrue, scenarios depicting zombies or disembodied minds less as evidence against materialism than as reason to reject any evidential link between conceivability and possibility at all.

To be sure, modal rationalists such as George Bealer and David Chalmers³ have attempted to rise to the challenge, contending that it is the ideal, rather than the mere prima facie, conceivability of an F that is not a G that provides the best evidence that such a thing is possible.⁴ But we are not ideal conceivers, and though Chalmers (2002, 155) suggests that there is an attainable intermediate position between prima facie and ideal conceivability that can provide quite good (if defeasible) evidence for possibility — he calls it secunda facie coherence — he says little about what this requires other than that the imagined scenario must remain coherent upon further reflective scrutiny, and continue to seem aptly describable as an F that is not a G .

Though I agree that there are serious questions about the relation of conceivability and possibility, it seems crucially important to philosophical inquiry — at least about phenomena such as knowledge, justification, intentional action, free will, personal identity, and moral responsibility — that conceivability provide some sort of (good, though defeasible) evidence for possibility. Thus it seems crucial to have a plausible account of what Chalmers calls secunda facie coherence — both for deliverances of the imagination that purport to stand as evidence for a priori and for a posteriori philosophical theses. But this phenomenon needs to be characterized in greater, and sharper, detail to be able to put the doubts to rest.

My primary aim in this paper is to make some progress on this characterization. I'll attempt to do so, however, by shifting attention from the familiar thought-experiments that target theories of knowledge, moral action, free will, and consciousness to some recent discussions of the 'puzzle of imaginative resistance': the question of why, as Tamar Gendler (2000) puts it in a paper that prompted interest in this topic among modal epistemologists, '[w]e make sense of stories where characters travel back in time, where spaceships go faster than the speed of light, where wizards turn straw into gold, and where lonely geniuses solve the continuum hypothesis' (57), but resist going along if the story 'includes the...sentence "In killing her baby, Giselda did the right thing; after all, it was a girl"' (62).⁵

Gendler focuses on our resistance to fictions that depict immoral actions as moral, but others note our resistance to further normative anomalies, such as the depiction of monster truck rallies as beautiful or sublime (Yablo...