Abstract
Although in some contexts the notions of an ordinary argument’s presumption, assumption, and presupposition appear to merge into the one concept of an implicit premise, there are important differences between these three notions. It is argued that assumption and presupposition, but not presumption, are basic logical notions. A presupposition of an argument is best understood as pertaining to a propositional element (a premise or the conclusion) e of the argument, such that the presupposition is a necessary condition for the truth of e or for a term in e to have a referent. In contrast, an assumption of an argument pertains to the argument as a whole in that it is integral to the reasoning or inferential structure of the argument. A logical assumption of an argument is essentially a proposition that must be true in order for the argument aside from that proposition to be fully cogent. Nothing that is both comparable and distinguishing can be said about presumptions of arguments. Rather, presumptions of arguments are distinctively conventional; they are introduced through conventional rules (e.g., those that concern how to treat promises). So not all assumptions and not all presuppositions of arguments are presumptions of those arguments, although all presumptions of arguments are either assumptions or presuppositions of those arguments. This account avoids making the (monological) notion of presumption vacuous and dissolving the distinction between assumption and presumption, which is a vulnerability of alternative views such as Hansen’s and Bermejo-Luque’s, as is shown.
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Notes
Hypothetical Syllogism is the conditionalized form of the Barbara syllogism. Hitchcock (2002) presents a challenge, with respect to an enthymematic argument putatively a Barbara syllogism, to show why the implicit assumption completes a Barbara syllogism and not a recherché Disjunctive Syllogism. Paglieri and Woods convincingly answer this challenge (2011a, pp. 488–489).
Note that in this paper I am not directly concerned with the matter of how, in the first place, one finds implicit assumption candidates (that can then be subjected to my criteria). For procedures that are designed to help with this and that embody criteria that are in some respects comparable to my principal criterion, see Donn (1990, p. 159ff.) and Malone (2003, p. 246ff.).
1 satisfies the other criteria proposed above for determining implicit assumptions of arguments if we suppose, as Ennis apparently does (p. 75), that 1 is not a necessary truth. If 1 were taken to be a necessary or conceptual truth such that the concept of animal is involved in the concept of dog, then as ‘materially’ or ‘substantively’ valid, it would not be at all clear that the stated argument has any such implicit assumption. For discussion, see Plumer (2000, pp. 3–4).
Here is a richer nondeductive case (from the Feb. 1992 Law School Admission Test, Copyright © 1992 by Law School Admission Council):
“The brains of identical twins are genetically identical. When only one of a pair of identical twins is a schizophrenic, certain areas of the affected twin's brain are smaller than corresponding areas in the brain of the unaffected twin. No such differences are found when neither twin is schizophrenic. Therefore, this discovery provides definitive evidence that schizophrenia is caused by damage to the physical structure of the brain.”
The test question asks “Which one of the following is an assumption required by the argument?” and the credited response says “The relative smallness of certain parts of the brains of schizophrenics is not the result of schizophrenia or of medications used in its treatment.”
I interpret the causal relationships propounded by the argument to be that damage to the physical structure of the brain is the common cause of both schizophrenia and the relative smallness of certain parts of the brains of schizophrenics. This is how the argument explains the “discovery,” i.e., the apparently perfect correlation of schizophrenia and the relative smallness, after in effect ruling out a genetic explanation. The credited response contributes to the argument’s cogency in an essential way by ruling out two further salient alternative explanations of this correlation. If the negation of this response were the case, then (at least) one of these alternative explanations would be true, and it would fully explain the discovery or evidence without any need to appeal to a damaging mechanism, contrary to the argument.
Actually, I am not sure that the idea of an argument that is wholly or irredeemably fallacious makes sense. What would the alleged premises or assumptions, let alone the alleged conclusion, be doing in such a case?
A presuppositional (vs. premissory) presumption of an argument would be a presupposition of a premissory presumption of that argument.
For helpful comments on earlier drafts, I am grateful to Lyra Hostetter, Kenneth Olson, Teresa Plumer, and audience members at the Conference on Presumptions, Presumptive Inferences and Burden of Proof, University of Granada, April 2016.
References
Adler, J. 2006. Confidence in argument. Canadian Journal of Philosophy 36 (2): 225–258.
Allen, D. 1998. Should we assess the basic premises of an argument for truth or acceptability? In Proceedings of the 2nd conference of the Ontario society for the study of argumentation, 1–9. Windsor, ON: OSSA (CD ROM).
Beaver, D.I., and B. Geurts. 2011. Presupposition. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/presupposition/.
Bermejo-Luque, L. 2013. Assessing presumptions in argumentation: Being a sound presumption vs. being presumably the case. In Virtues of argumentation: Proceedings of the 10th international conference of the Ontario society for the study of argumentation, ed. D. Mohammed and M. Lewiński, 1–13. Windsor, ON: OSSA (CD-ROM).
Bermejo-Luque, L. 2016. Being a correct presumption vs. being presumably the case. Informal Logic 36 (1): 1–25.
Burke, M. 1985. Unstated premises. Informal Logic 7 (2–3): 107–118.
Carroll, L. 1895. What the tortoise said to Achilles. Mind 4: 278–280.
Copi, I.M. 1978. Introduction to logic, 5th ed. New York: Macmillan.
Donn, M. 1990. Help in finding missing premises. Teaching Philosophy 13 (2): 159–164.
Ennis, R.H. 1982. Identifying implicit assumptions. Synthese 51 (1): 61–86.
Freeman, J.B. 2005. Acceptable premises: An epistemic approach to an informal logic problem. Cambridge: Cambridge University Press.
Godden, D.M., and D. Walton. 2007. A theory of presumption for everyday argumentation. Pragmatics and Cognition 15 (2): 313–346.
Govier, T. 1972. Presuppositions, conditions, and consequences. Canadian Journal of Philosophy 1 (4): 443–456.
Govier, T. 1987. Problems in argument analysis and evaluation. Dordrecht: Foris.
Govier, T. 1992. What is a good argument? Metaphilosophy 23 (4): 393–409.
Govier, T. 2010. A practical study of argument, 7th ed. Belmont, CA: Wadsworth.
Grennan, W. 1994. Are “gap-fillers” missing premises? Informal Logic 16 (3): 185–196.
Hansen, H.V. 2003. Theories of presumptions and burdens of proof. In Informal logic at 25: Proceedings of the Windsor conference, ed. J.A. Blair, et al., 1–12. Windsor, ON: OSSA (CD-ROM).
Hitchcock, D. 1985. Enthymematic arguments. Informal Logic 7 (2–3): 83–97.
Hitchcock, D. 2002. A note on implicit premisses. Informal Logic 22 (2): 159–160.
Johnson, R.H., and J.A. Blair. 1977/2006. Logical self-defense. Toronto: McGraw-Hill Ryerson/New York: International Debate Education Association.
Kauffeld, F.J. 1995. On the difference between assumptions and presumptions. In Argumentation and values: Proceedings of the Ninth SCA/AFA conference on argumentation, ed. S. Jackson, et al., 509–514. Annadale, VA: Speech Communication Association.
Kauffeld, F.J. 2013. Commentary on: Lilian Bermejo-Luque’s “Assessing presumptions in argumentation: Being a sound presumption vs. being presumably the case.” In Virtues of argumentation: Proceedings of the 10th international conference of the Ontario society for the study of argumentation, ed. D. Mohammed and M. Lewiński, 1–5. Windsor, ON: OSSA (CD-ROM).
Llewelyn, J.E. 1962. Presuppositions, assumptions and presumptions. Theoria 28 (2): 158–172.
Malone, M. 2003. Three recalcitrant problems of argument identification. Informal Logic 23 (3): 237–261.
Nolt, J.E. 1986. Entailment, enthymemes, and formalization. Journal of Philosophy 83 (10): 572–573.
Nosich, G.M. 1982. Reasons and arguments. Belmont, CA: Wadsworth.
Paglieri, F., and J. Woods. 2011a. Enthymematic parsimony. Synthese 178 (3): 461–501.
Paglieri, F., and J. Woods. 2011b. Enthymemes: From reconstruction to understanding. Argumentation 25 (2): 127–139.
Paglieri, F. 2015. Bogency and goodacies: On argument quality in virtue argument theory. Informal Logic 35 (1): 65–87.
Plumer, G. 1999. Necessary assumptions. Informal Logic 19 (1): 41–61.
Plumer, G. 2000. The paradoxical associated conditional of enthymemes. In Argumentation at the century's turn, ed. C.W. Tindale, et al., 1–8. Windsor, ON: OSSA (CD-ROM).
Rescher, N. 1977. Dialectics. A controversy-oriented approach to the theory of knowledge. Albany: State University of New York Press.
Rescorla, M. 2015. Convention. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/convention/.
Shanon, B. 1976. On the two kinds of presuppositions in natural language. Foundations of Language 14 (2): 247–249.
Sloman, A. 1964. Rules of inference, or suppressed premisses? Mind 73 (289): 84–96.
Smiley, T. 1995. A tale of two tortoises. Mind 104 (416): 725–735.
Ullman-Margalit, E. 1983. On presumption. Journal of Philosophy 80 (3): 143–163.
Walton, D., C. Reed, and F. Macagno. 2008. Argumentation schemes. Cambridge: Cambridge University Press.
Walton, D. 2014. Burden of proof, presumption and argumentation. Cambridge: Cambridge University Press.
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Gilbert Plumer—Retired
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Plumer, G. Presumptions, Assumptions, and Presuppositions of Ordinary Arguments. Argumentation 31, 469–484 (2017). https://doi.org/10.1007/s10503-016-9419-1
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DOI: https://doi.org/10.1007/s10503-016-9419-1