Abstract

Two recent papers have presented experimental evidence against the hypothesis that there is a semantic connection between OUGHT and CAN, rather than a pragmatic and defeasible one. However, there are two flaws with their designs. One is temporal ambiguity: just asking whether “x ought to A” is underspecified as to _when_ the obligation exists. Another is failing to distinguish between _prior_ obligations and _all-things-considered_ obligations. To test these potential confounds, the chapter author ran two experiments. The first paired some of the original stories with a visual timeline specifying the time of the obligation. The second flipped the wording of the original “obligated but can’t” question into the reversed: “can’t, but still obligated.” In both experiments, there were large and significant differences between the original and modified conditions. These results undermine the conclusions of the previous experiments and remain consistent with the Semantic Hypothesis.