Abstract

If you are told or otherwise believe an either—or proposition, the question may easily arise what makes it true. ‘The potato crop in Ruritania was halved by blight in 1928’ — ‘Well then, either the expected, planned-for crop was in excess of the people's needs, or there was a shortage of potatoes that year, or a lot were imported …’. That seems a fair deduction, and we may ask which was true. If only one was, then we'd say it made the disjunction true. If all were, then all of them did.