The Logic of Partial Supposition

According to orthodoxy, there are two basic moods of supposition: indicative and subjunctive. The most popular formalisations of the corresponding norms of suppositional judgement are given by Bayesian conditionalisation and Lewisian imaging, respectively. It is well known that Bayesian conditionalisation can be generalised (via Jeffrey conditionalisation) to provide a model for the norms of partial indicative supposition. This raises the question of whether imaging can likewise be generalised to model the norms of `partial subjunctive supposition'. The present article casts doubt on whether the most natural generalisations of imaging are able to provide a plausible account of the norms of partial subjunctive supposition.