ABSTRACT
This chapter considers supposition along other dimensions, namely propositionality, inferentiality, will-dependence and truth-dependence. The propositionality of supposition is tied to another feature supposition has been credited with, namely inferentiality. This feature has been extensively discussed for propositional beliefs. Beliefs are related to one another by inferential dispositions: having one or more beliefs grounds that the subject ought to have certain other beliefs. Inferential functional similarities between cognitive imagination and belief are suggested by cognitive research on modal reasoning and engagement with fiction and pretence. The strong dependence of supposition on the will matches quite well with its normativity. The will-dependence of supposition is central in considering its relationship with truth. Spontaneous suppositions are infrequent, if there are any. It seems that one cannot spontaneously come up with a supposition, as with a thought or with an imagining. Supposition cannot be as intrusive as imagination can be; one cannot be haunted by a supposition as by an imagining.
