
arXiv: 2309.09451
In a seminal work Fine (2018), Fine classifies several forms of ignorance, among which are Fitchean ignorance, first-order ignorance, Rumsfeld ignorance, and second-order ignorance. It is shown that there are some relationships among some of them, including that in S4, all higher-order ignorance are reducible to second-order ignorance. This is thought of as a disadvantage by some researchers. It is then natural to ask how to avoid this consequence. We deal with this issue in a much more general framework. In details, we treat the forms of Fitchean ignorance and first-order ignorance as primitive modalities and study them as first-class citizens under neighborhood semantics, in which Rumsfeld ignorance and second-order ignorance are definable. The main contributions include model-theoretical results such as expressivity and frame definability, and axiomatizability. Last but not least, by updating the neighborhood models via the intersection semantics, we extend the results to the dynamic case of public announcements, which gives us some applications to successful formulas. We also show that the result in Fine (2018) stating all higher-order ignorance are reducible to second-order ignorance does not hold in any of our logical systems.
FOS: Computer and information sciences, Computer Science - Logic in Computer Science, FOS: Mathematics, Mathematics - Logic, Logic (math.LO), Logic in Computer Science (cs.LO)
FOS: Computer and information sciences, Computer Science - Logic in Computer Science, FOS: Mathematics, Mathematics - Logic, Logic (math.LO), Logic in Computer Science (cs.LO)
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 0 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
