Natural deduction, separation, and the meaning of logical operators

N. D. Belnap, ‘Tonk, Plonk and Plink’, in P. F. Strawson (ed.), Philosophical Logic, Oxford University Press, Oxford, 1967, pp. 132–137; reprinted from Analysis, Blackwell, 1962, Vol. 22, pp. 130–134. N. D. Belnap, Jr. and R. H. Thomason, ‘A Rule-Completeness Theorem’, Notre Dame Journal of Formal Logic, Vol. IV, No. 1, pp. 39–43. N. D. Belnap, Jr., H. Leblanc, and R. H. Thomason, ‘On Not Strengthening Intuitionistic Logic’, Notre Dame Journal of Formal Logic, Vol. IV, No. 4, pp. 313–320. Kent Bendall, ‘Negation as a Sign of Negative Judgement’, Notre Dame Journal of Formal Logic, forthcoming. Evert W. Beth, The Foundations of Mathematics, North-Holland Publishing Company, Amsterdam, 1959. Frederic Brenton Fitch, Symbolic Logic, The Ronald Press Co., New York 1952. Gottlob Frege, ‘Negation’, in Peter Geach and Max Black (ed.), Translations from the Writings of Gottlob Frege, Basil Blackwell, Oxford, 1952. Peter Geach, ‘Assertion’, The Philosophical Review, Vol., LXXIV (1965), pp. 449–465. Gilbert H. Harman, ‘Induction’, in Marshall Swain (ed.), Induction Acceptance, and Rational Belief, D. Reidel Publishing Co., Dordrecht, 1970, pp. 83–99. Gilbert H. Harman, Thought, Princeton University Press, Princeton, N.J., 1973. Richard C. Jeffrey, Formal Logic; Its Scope and Limits, McGraw-Hill Book Co., New York, 1967. Hughes Leblanc, ‘Two Shortcomings of Natural Deduction’, Journal of Philosophy, Vol. LXIII (1966), pp. 29–37. Hugues Leblanc and William A. Wisdom, Deductive Logic, Allyn and Bacon, Inc., Boston, 1972. D. Ponasse, Mathematical Logic, Goden and Brench, New York, 1973. A. N. Prior, ‘The Runabout Inference-Ticket’, in P. F. Strawson, op. cit, pp. 129–131; reprinted from Analysis, Blackwell, 1960, Vol. 21, pp. 39–59. WillardVan Orman Quine, Methods of Logic, Third Edition, Holt, Rinehart & Winston, New York, 1972. WillardVan Orman Quine, Philosophy of Logic, Prentice-Hall, Englewood Cliffs, N.J., 1970. Raymond M. Smullyan, First-Order Logic. Springer-Verlag, New York, 1968.