Abstract
David Lewis and Peter van Inwagen have claimed that there are no “knockdown” arguments in philosophy. Their claim appears to be at odds with common philosophical practice: philosophers often write as though their conclusions are established or proven and that the considerations offered for these conclusions are decisive. In this paper, I examine some questions raised by Lewis’s and van Inwagen’s contention. What are knockdown arguments? Are there any in philosophy? If not, why not? These questions concern the nature of the philosophical enterprise and our answers have implications for the limits on the attitudes of informed, rational thinkers.
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Notes
In Sect. 2 I discuss Lewis’s exceptions [viz., “(…Gödel and Gettier may have done it.)”]. It’s worth comparing this passage to a couple others. Lewis declared: “I am an atheist. So you might suspect that my purpose is to debunk free-will theodicy, and every other theodicy besides, so as to provide—at last!—a triumphant knockdown refutation of Christianity. I am convinced that philosophical debate almost always ends in deadlock, and that this case will be no exception” (1993: 150). In a posthumous paper (edited by Philip Kitcher using Lewis’s notes and Kitcher’s memory of conversation with Lewis), Lewis writes: “In my view, even the most ambitious version (of the argument from evil) succeeds conclusively. There is no evasion, unless the standards for success are set unreasonably high” (2007: 231). Perhaps this late text represents a change to Lewis’s earlier view: he might be read as suggesting there is a knockdown philosophical argument against theism. An alternative reading is that he thought requiring a knockdown argument as the “standard for success” was “unreasonable” and that the argument from evil didn’t succeed by such a standard. (But then why would Lewis say that any version of the argument “succeeds conclusively”?)
Van Inwagen remarks that most present-day analytical philosophers “believe that there are knockdown arguments in philosophy. (And it is certainly true that they believe that there could be.)” (2004: 339). Notably, he admits that writing as if there are no knockdown arguments in philosophy is virtually impossible for philosophers, himself included (2006: 37–38), cf. (2004: 338–339).
To my knowledge, no recent journal article or book chapter systematically explores knockdown arguments. (Wreen (1995) is entitled “Knockdown Arguments”, though it’s concerned with the argumentum ad baculum, not what we’ll call knockdown arguments.)
An anonymous referee helpfully pressed me to clarify this objection.
I am at moments inclined to use “maximally irrational” in place of “strongly irrational” in D, but that would imply that there are not degrees of strength among knockdown arguments. I choose to leave the issue unsettled.
Perhaps what philosophers do mean isn’t what they should mean. As best I can tell, D mostly fits with van Inwagen’s use of “knockdown argument” in his (2009) and (2004), and one proposal for “philosophical success” (2006: 39–40) (namely, an argument that “should convert any rational person”). And van Inwagen tacitly assumes in (2004) that he and Lewis use that term in the same way. I submit van Inwagen’s tacit assumption as fairly good evidence that D also fits with Lewis’s use of the term. The philosophers I’ve informally polled have agreed that something like B or C or D, but not A, is what they and their colleagues mean by the term.
For the details, I am indebted to Benjamin Wilson.
The distinction between substantive and minor theses won’t be clear cut. Van Inwagen (2006: 40) says that there may be “borderline” cases of substantive theses.
Conversations with E.J. Coffman and Stew Cohen helped here.
Russell (1995: 204). Compare to Russell’s remarks near the end of The Problems of Philosophy, which should at least remind us of the position van Inwagen has staked out: “[I]t cannot be maintained that philosophy has had any very great measure of success in its attempts to provide definite answers to its questions. If you ask a mathematician, a mineralogist, a historian, or any other man of learning, what definite body of truths has been ascertained by his science, his answer will last as long as you are willing to listen. But if you put the same question to a philosopher, he will, if he is candid, have to confess that his study has no achieved positive results such as have been achieved by other sciences” (1997: 154–155).
Van Inwagen (2009: 10ff).
Van Inwagen (2004: 338–339).
Parfit makes a similar point about ethics (1984: 453–454).
Someone may insist that the thesis that there are no knockdown arguments in philosophy is a piece of metaphilosophy and that metaphilosophy is not itself a branch of philosophy. So, if there can be knockdown arguments in metaphilosophy, that thesis might itself be conclusively established. It is less than obvious, however, why anyone would think that metaphilosophy isn’t philosophy. (What else could it be?)
Could we call this “Physics Envy”?
Van Inwagen writes: “Consider those enviable theoretical disciplines in which ‘pervasive agreement’ is the order of the day. Consider any proposition that, as the result of the researches of the experts in these disciplines, is generally agreed to be true … Will there not in every case be at least one knockdown argument for the truth of this proposition (or at least an argument that the experts regard as a knockdown argument)?” (2004: 339).
Compare: “Unlike the physical sciences, history does not have “a large body of settled, usable, uncontroversial theory” at its disposal but, like the physical sciences, it does have a large body of established and incontrovertible fact to work with. In philosophy, however, there is neither settled theory nor incontrovertible fact” (2004: 335). Van Inwagen’s last observation applies to his philosophical position on the absence of knockdown arguments in philosophy: his position is neither settled theory nor incontrovertible fact (though he might think it is either one or the other).
Van Inwagen (2009: 2–4).
Terry Horgan and Jonathan Schaffer independently reminded me that van Inwagen (1990) paraphrases statements about (e.g.) continents in terms of ‘simples arranged continent-wise’. This doesn’t supply reason for van Inwagen to doubt the entailment in question, for after the required translation, he will say that it is an established fact that there are simples arranged continent-wise. And if it is an established fact there are simples arranged continent-wise, it is an established fact that there are simples. Van Inwagen is back to ultimate reality.
Or ‘simples arranged continent-wise’. See footnote 26.
Stephanie Wykstra raised an objection along these lines and Gilad Tanay helpfully discussed replies.
Thanks to Alex Skiles and an anonymous referee for an objection like this.
Josh Rasmussen shared an objection like this.
Josh Rasmussen suggested I discuss an objection like this.
The Metaontologist objects: “When we say ‘there is a prime number between 4 and 6’, we needn’t be committing ourselves to anything ontologically significant—that is, we needn’t be committing ourselves to a truth when the ontological expressions in the sentence are used in their technical senses appropriate for describing reality’s structure. Let us say, then, that there is a special sense of ‘there is’ that is not ontologically committing. Either ‘there is something’ is ontologically committing or it isn’t. If it is, then nothing scientists tell us implies it, in step with Objection 5. If it isn’t ontologically committing, then it’s no philosophical thesis.” This is a fair objection, in light of recent debates over metaontology, and some metaontologists will be moved by the thought. I won’t discuss this matter here. For more on the recent debates, see Korman (2013) and the papers cited and discussed therein. (Thanks to Alex Skiles and Josh Rasmussen for bringing this issue to my attention.)
That there are knockdown arguments in philosophy is certainly a (meta)philosophical thesis. Is it substantive? I suspect so but leave discussion aside, in part because I am unsure how to draw the distinction between substantive and minor theses. For more, see Sect. 2 above.
Ancestors of this paper were presented at Yale University in October 2006 and Arizona State University in March 2007. Thanks to the audiences and commentators, Stephanie Wykstra and Craig Carley, on those occasions. Thanks also to the young child at Yale who, out in the hallway, briefly interrupted the Q&A when he discovered the refreshment table and exclaimed, “They have cookies!” Two audience members on the same occasion, Michael Brent and Jeffrey Wisdom, encouraged me to keep working on this topic. For comments and conversation, I am grateful to Alex Skiles, Andrew Bailey, Tomás Bogardus, David Christensen, E.J. Coffman, Stew Cohen, Thomas Crisp, William Dyer, Ian Evans, Chris Freiman, Terry Horgan, Nathan King, Victor Kumar, Keith Lehrer, Laurie Paul, Daniel Sanderman, Mark Timmons, Benjamin Wilson, Jeffrey Wisdom, and several anonymous referees. Josh Rasmussen commented on several drafts and offered much good philosophical advice. If not for Jennifer Ballantyne’s wise intevention, the epigraph for this paper would have been a Chumbawamba lyric. Some of my work on the paper was supported by the Social Sciences and Humanities Research Council of Canada.
I unfortunately can’t now express my gratitude to the late John L. Pollock (1940–2009), who devised many knockdown arguments. I dedicate this essay to his memory.
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Ballantyne, N. Knockdown Arguments. Erkenn 79 (Suppl 3), 525–543 (2014). https://doi.org/10.1007/s10670-013-9506-8
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DOI: https://doi.org/10.1007/s10670-013-9506-8