 This is, with minor changes, the way in which Łukasiewicz introduces the third value in his first published paper on the subject, which bears the title “On the Concept of Possibility”. This short paper is based on a talk given on 5 June 1920 in Lwów. Two weeks later a second talk in the same place was more transparently titled “On Three-Valued Logic”. In this, Łukasiewicz sets out principles governing implication and equivalence involving the third value. These in effect determine the  truth-tables[2]  for these connectives: