In this paper we elaborate a conception of entailment based on what we call the Ackermann principle, which explicates valid entailment through a logical connection between (sets of) sentences ...

Vol. 42, No. 2/3, Proceedings of the Finnish-Polish-Soviet Logic Conference (1983), pp. 139-164 (26 pages) A system of natural deduction is presented whose set of theses is identical with that of the ...

Due: Assignment #4 (Lemmon p. 62, #2 (all), #5 (omit i,j,k,l), #7; p. 73, #1 (part one, omit j,k); #3 (part one).) Reading: Lemmon Section 3.3 [Also read Sections 3.1 & 3.2 if you have not already.] ...