We don’t know we don’t know: asserting ignorance

Massimiliano Carrara, Daniele Chiffi*, Ciro De Florio, Ahti Veikko Pietarinen

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

10 Citations (Scopus)


The pragmatic logic of assertions shows a connection between ignorance and (informal) decidability. In it, we can express pragmatic factual ignorance and first-order ignorance as well as some of their variants. We also show how some pragmatic versions of second-order ignorance and of Rumsfeld-ignorance may be formulated. A specific variant of second-order ignorance is particularly relevant. This indicates a strong pragmatic version of ignorance of ignorance, irreducible to any previous form of ignorance, which defines limits to what can justifiably be asserted about higher-order ignorance. Finally, we relate the justified assertion of second-order ignorance (that cannot be known) with scientific assertions.

Original languageEnglish
Pages (from-to)3565-3580
Number of pages16
Issue number4
Early online date29 Jun 2019
Publication statusPublished - Apr 2021

Scopus Subject Areas

  • Philosophy
  • Social Sciences(all)

User-Defined Keywords

  • Assertion
  • Ignorance
  • Pragmatic logic
  • Uncertainty


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