The ‘Private Language’ sections of the Philosophical Investigations §§ 243–315 serve to undermine the idea that our ordinary felt sensations, e.g., of heat, or cold, or pain, together with our experienced impressions of colour or of sound, are ‘private’ or ‘inner’ objects, where an object mirrors in the mental realm what we associate with that of the physical. This paper explores Wittgenstein's method in these sections, together with the work of several of his commentators who agree with his ‘therapeutic’ approach (...) to the denial of a possible private language. More significantly, however, it discovers a paradox in the fact that a number of philosophers who claim that his ‘Argument Against Private Language’ is unsuccessful point in reaching this conclusion to the very features concerning first-person sensation ascription that Wittgenstein employs to reveal that our ordinary sensations are not ‘private’ to us in that sense identified in § 243, which talks of ‘a language used to refer to what only its speaker can know’, viz, ‘his immediate private sensations’. This helps to explain why there is still no general agreement on the significance of §§ 243–315. (shrink)

Despite the fact that the reductio ad absurdum argument is a valid deductive form, while the slippery slope argument is most often presented as a fallacious form of inductive argument, the two argument types bear some striking similarities. Investigation of these similarities reveals some more universal difficulties in the teaching of informal logic, and, in particular the difference between strong informal arguments and fallacious ones.

Used informally, the Reductio ad Absurdum (RAA) consists in reasoning appealing to the logically implied, absurd consequences of a hypothetical proposition, in order to refute it. This kind of reasoning resembles the Argument from Consequences, which appeals to causally induced consequences. These types of argument are sometimes confused, since it is not worked out how these different kinds of consequences should be distinguished. In this article it is argued that the logical consequences in RAA-argumentation can take different appearances (...) and that it therefore must be concluded that RAA cannot be characterised by a specific content, but must instead be characterised as an argument form. Furthermore, clues are provided to distinguish RAA reasoning from the Argument from Consequences. (shrink)

According to standard trope nominalism, there are simple tropes that do not have parts or multiply distinct aspects. Douglas Ehring’s reductio ad absurdum against this standard view concludes that there are no simple tropes. In this paper, we provide a response to Ehring defending the standard view. Ehring’s argument may be refuted by (1) distinguishing the ontological form of tropes from their contribution to the ontological content of the world, and (2) construing tropes as having primitive identity. (...) At the same time, standard trope nominalism is elaborated on by distinguishing between ontological form and content, for which there are also independent reasons. (shrink)

This paper presents the main aspects of the views of the Tibetan logician Phya pa Chos kyi seng ge (1109–1169) on argumentation “by consequence” (thal ʼgyur, Skt. prasaṅga) based on his exposition of the topic in the fifth chapter of his Tshad ma yid kyi mun sel and on a parallel excursus in his commentary on Dharmakīrti’s Pramānaviniścaya. It aims at circumscribing primarily the nature and function of consequences (thal ʼgyur/thal ba) for this author—in particular the distinction between “proving consequences” (...) and “refuting consequences”—and the form prescribed for their enunciation in the context of debate. In addition to pointing out differences with the systems adopted by his predecessors, contemporaries and successors, the paper also discusses some of the similarities and differences between Phya pa’s understanding of argumentation by consequence and the notion of reductio ad absurdum in Western logic. (shrink)

The uses and interpretation of reductio ad absurdum argumentation in mathematical proof and discovery are examined, illustrated with elementary and progressively sophisticated examples, and explained. Against Arthur Schopenhauer’s objections, reductio reasoning is defended as a method of uncovering new mathematical truths, and not merely of confirming independently grasped mathematical intuitions. The application of reductio argument is contrasted with purely mechanical brute algorithmic inferences as an art requiring skill and intelligent intervention in the choice of hypotheses and (...) attribution of contradictions deduced to a particular assumption in a contradiction’s derivation base within a reductio proof structure. (shrink)

The book is a translation of the Sophist with a running commentary. Three main points are argued: the dialogue does not present positive doctrine but has the structure of a reductio ad absurdum, Plato's point is to criticize the metaphysics of Parmenides. By failing to account for resemblance, Eleaticism implies an inadequate theory of relations, which makes impossible any understanding of "essence." Consequently, Eleaticism can be taken as the philosophical underpinning for the antithesis of philosophy, lending legitimacy to (...) sophistry, the criticism constitutes an indirect argument for the theory of forms. ;The method of division employed in the Sophist does not proceed "along natural joints" as called for in the Phaedrus, nor can it, since the Eleatic logic that underlies the method used in the Sophist allows for no intermediate in the strict opposition of 'being' and 'not-being.' The only definitions that can be made on this basis are negative definitions. This leads to an inability to account for images on Eleatic terms, providing a refuge for the sophist--he cannot be a maker of deceptive images if there are no images and no falsity. However, the modification of the Eleatic rejection of not-being is incomplete and insufficient. ;The arguments allow only for relations of identity and difference or whole and part, excluding any account of resemblance, the basis for any theory of participation. On these grounds, not-being is defined in terms of difference, affording an incomplete explanation of false statement, while abandoning the initial problem of images. Moreover, the concluding argument directly implies the reduction of 'being' to the newly introduced definition of 'not-being.' The ending turns back to the beginning: the sophist has an art that is no art, and definitions can only be definitions in terms of difference, negative definitions allowing no adequate account of images and no essences. The dialogue ends in a subtle aporia pointing to the failure to acknowledge that to say images both are and are not indicates an order of ontological dependence. (shrink)

It is well known that reductio ad absurdum arguments raise a number of interesting philosophical questions. What does it mean to assert something with the precise goal of then showing it to be false, i.e. because it leads to absurd conclusions? What kind of absurdity do we obtain? Moreover, in the mathematics education literature number of studies have shown that students find it difficult to truly comprehend the idea of reductio proofs, which indicates the cognitive complexity of (...) these constructions. In this paper, I start by discussing four philosophical issues pertaining to reductio arguments. I then briefly present a dialogical conceptualization of deductive arguments, according to which such arguments are best understood as a dialogue between two participants—Prover and Skeptic. Finally, I argue that many of the philosophical and cognitive difficulties surrounding reductio arguments are dispelled or at least further clarified once one adopts a dialogical perspective. (shrink)

In this paper, I present an argument to show that the doctrine of divine temporality (the view that God is in time, but everlastingly eternal) is incoherent. The doctrine of divine temporality entails that God has traversed an actually infinite series of moments in order to reach the present. But I show that an actually infinite series of moments cannot be traversed. Hence, God could not have traversed his infinite past to reach the present. Therefore, the doctrine of divine temporality (...) is necessarily false. I defend this argument against various responses and objections. (shrink)

Theists believe that God is eternal, but they differ as to just what God's eternality means . The traditional, historic view of most Christian philosophers is that eternality means that God is timeless. He is ‘outside’ of time and not subject to any kind of temporal change. Indeed, God is the creator of time. Lets call this view divine timelessness.

Can there be a good argument for the total denial of rule following? The question concerns the "total" denial, where the targeted rules include those meta-rules presumably required for philosophical argumentation. In this paper the author contends that such a self-undermining argument can never be a good argument even in a "reductio ad absurdum" form, but that the defender of rule following cannot dismiss a challenge on this ground when the opponent adopts "the virus strategy".

This essay tries to show that there exist several passages where Kierkegaard (and his pseudonyms) sketches an argument for the existence of God and immortality that is remarkably similar to Kant's so-called moral argument for the existence of God and immortality. In particular, Kierkegaard appears to follow Kant's moral argument both when it comes to the form and content of the argument as well as some of its terminology. The essay concludes that several passages in Kierkegaard overlap significantly with (...) Kant's moral argument, although Kierkegaard ultimately favors revealed faith over natural theology in general and Kant's moral faith in particular. Whereas Kant uses the moral argument to postulate the existence of God and immortality, Kierkegaard mainly uses it as a reductio ad absurdum of non-religious thinking. (shrink)

In “Confucianism and Same-Sex Marriage,” published recently in Politics and Religion, Professor Tongdong Bai argues for a “moderate Confucian position on same-sex marriage,” one that supports its legalization and yet endeavors “to use public opinion and social and political policies to encourage heterosexual marriages, and to prevent same-sex marriages from becoming the majority form of marriages” (Bai 2021:146). Against the backdrop of downright homophobia prevalent among vocal Confucians in mainland China today, Bai claims that his pro-legalization rendition “show[s] a (...) different version of Confucianism that challenges the received perception of Confucianism that it is deeply conservative, a perception that often lies at the core of the rejection of its contemporary relevance, especially by the so-called ‘liberals’ in China and elsewhere” (Bai 2021:133). Furthermore, Bai claims that his moderate Confucianism is normatively preferrable to “the typical liberal or individualist position” of a marriage equality supporter, because the specter of polygamy – the conservative trope of invoking polygamy as a reductio ad absurdum against same-sex marriage – imposes “a serious challenge” to liberals but not to moderate Confucians (Bai 2021:146, 153). -/- Both of Bai’s claims falter upon scrutiny, however. Granted, it is applaudable that Bai tries to dissuade his more conservative Confucian colleagues from opposing the legalization of same-sex marriage. But as Section 1 of this Response will show, the alternative rendition of Confucianism he presents, along with the way he presents it, is premised on a highly contested conception of what shared Confucian values are; does injustice to Confucians who embrace marriage equality more unreservedly (i.e., without caveats à la Bai); fails to produce new arguments that “enrich the theoretical basis for same-sex marriage” (Bai 2021:133); and, ironically, reinforces – rather than “challenges” – the “received perception” of Confucianism as deeply conservative. Meanwhile, Section 2 will show that Bai’s comparison between liberalism and moderate Confucianism relies both upon an apparent unfamiliarity with the extensive and nuanced liberal discussions on polygamy, and upon fallacious methods of assessing comparative normative valence. -/- Finally, Section 3 will offer some concluding thoughts from the perspective of decolonial theory, examining the dynamic of spectacularized postcoloniality that propels the production and consumption of dubious theoretical projects like Bai’s. As it turns out, this case serves not only as a cautionary tale of how not to conduct comparative normative theorizing, but also as a cautionary tale of how not to let the spectacle of postcoloniality derail the pursuit of academic decolonization. (shrink)

I defend the ethical fittingness theory (EFT), the thesis that whenever it is legitimate ethically to evaluate a representational artwork for the perspective it embodies, such evaluation systematically bears on the work's artistic value. EFT is a form of radical moralism, claiming that the systematic relationship between the selected type of ethical evaluation and artistic evaluation always obtains, for works of any kind. The argument for EFT spells out the implications of ethically judging an artwork for its perspective, where (...) such an ethical evaluation is understood as an assessment of how well the work's ethical perspective fits extra-fictional reality—how appropriate, correct, or true the perspective is. The argument shows that the ethical legitimacy of judging a work for its perspective ipso facto proves the judgment's art-critical relevance. Hence, the argument effectively amounts to a reductio ad absurdum of theories that admit the legitimacy of ethically judging artworks this way, but deny or qualify the judgment's relevance to artistic merit. Since EFT is stated conditionally, the argument need not indicate how often artworks are subject to this type of ethical evaluation. Nonetheless, I make a case for the relevance of EFT to actual art criticism and contemporary philosophical debate. (shrink)

This thesis is a critique of Jaakko Hintikka’s reconstruction of Kantian intuition in logical and mathematical reasoning. I argue that Hintikka’s reconstruction of Kantian intuition in particular and his reconstruction of Kant's philosophy of mathematics in general fails to be successful in two ways: First, the logical formula which contains an instantiated term (henceforth, instantial term) that is introduced by the rule of existential instantiation in the ecthesis part of a proof of an argument is not even a proper singular (...) proposition whose relation to its object is supposed to be immediate. It is not a proper singular proposition because its truth conditions are general, i.e., it makes a general statement about a class of individuals of the sort instantiated- a statement whose analysis is based on quantifiers. Second, I show that certain proofs in mathematics- those in the form of reductio ad absurdum- are not captured by Hintikka’s reconstruction of Kant’s philosophy of mathematics either. (shrink)

‘Moral bioenhancement’ refers to the use of pharmaceuticals and other direct brain interventions to enhance ‘moral’ traits such as ‘empathy,’ and alter any ‘morally problematic’ dispositions, such as ‘aggression.’ This is believed to result in improved moral responses. In a recent paper, Tom Douglas considers whether medical interventions of this sort could be “provided as part of the criminal justice system’s response to the commission of crime, and for the purposes of facilitating rehabilitation : 101–122, 2014).” He suggests that they (...) could “at least in some cases, permissibly be provided without valid consent : 101–122, 2014)” as a form of rehabilitative punishment. He argues for this conclusion by ‘parity of reasoning,’ starting from the currently accepted practice of non-consensual incarceration. His argument appears to be dependent on the successful defence of the following two claims: that non-consensual incarceration is a morally justifiable practice, and that there is no meaningful distinction between the forcible imposition of this practice, and the forcible imposition of medical interventions on prisoners. From both claims, he deduces : if non-consensual incarceration is morally justifiable, so is the non-consensual imposition of medical correctives, in some cases. In this paper, I begin by suggesting that the basic argument behind the Parity Claim results in a reductio ad absurdum, whereby any practice that is sufficiently similar to incarceration in the ways Douglas presents, would also be considered permissible. This appears to be an unpalatable conclusion, casting doubt on the soundness of a key premise. Douglas appears to offer no means of deciding which practices are sufficiently similar to incarceration in terms of harm and threat to agency, and of the practices that I will present, which do seem to be, it does not seem that he could rule them out in any principled way. Next I turn to dispute claim relating to the purported justifiability of incarceration on rehabilitative grounds. If successful, this attack causes a break in reasoning from the justifiability of incarceration, to the justifiability of medical interventions. Medical interventions would then require an alternative, independent justification, through outlining the ways in which they are conducive to a particular aim of punishment, without relying on the justifiability of incarceration. This argument has not been provided, and I suggest that attempts to do so may run into difficulty. I untangle and make explicit the various assumptions made in Douglas’ contention that medical interventions “might be thought conducive to rehabilitation in some offenders,” locating my critique in the wider debate on the causes of crime. Finally, I seek to challenge the normative weight of the Parity Claim, arguing that to show that two practices are comparable in some sense is not sufficient to show that both are equally as permissible. Other social purposes must be considered, leading me to suggest that the forcible imposition medical correctives falls beyond the appropriate remit of the criminal justice system. (shrink)

Don Marquis' future‐like‐ours account is regarded as the best secular anti‐abortion position because he frames abortion as a wrongful killing via deprivation of a valuable future. Marquis objects to the reductio ad absurdum of contraception as being immoral because it is too difficult to identify an individual that is deprived of a future. To demonstrate why Marquis’ treatment of the contraception reductio is flawed by his own future‐like‐ours line of reasoning, I offer an argument for why there (...) is indeed a candidate for harm—the ovum—for it can be viewed as providing the functional foundation for a new life through (1) mitochondrial DNA inheritance, (2) paternal histone restructuring during fertilization, and (3) ability to initiate parthenogenesis. As evidenced by these distinct and natural features of ova, candidate (2) “some ovum or other” should be morally prioritized as the direct candidate for harm in the contraception reductio. By assessing the philosophical inconsistencies in Marquis’ future‐like‐ours argument, this paper provides strong metaphysical grounds for rejecting the best secular anti‐abortion position. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Hume Studies Volume 29, Number 1, April 2003, pp. 29-41 Hume's Argument for the Temporal Priority of Causes TODD RYAN In a section entitled "Of Probability; and of the idea of cause and effect," Hume embarks on a search for the conceptual components of our idea of causation. Rejecting the possibility of analyzing the idea in terms of the qualities of objects, Hume claims to discover two constituent relations. (...) First, a cause and effect must be contiguous in space and time because "nothing can operate in a time or place, which is ever so little remov'd from those of its existence" (T 1.3.2.6; SBN 75).x Second, a cause must be temporally prior to its effect. Although experience is said to confirm this latter requirement "in most instances," Hume goes on to present an argument purporting to demonstrate that the temporal priority of a cause is an essential feature of every instance of causation.2 Despite the extensive treatment that his analysis of causation has occasioned, Hume's argument for the temporal priority of causes has received comparatively little attention. In this paper I hope to remedy this neglect by providing a more accurate explication of the argument than has previously been offered. Hume does not argue directly for the claim that a cause must be temporally prior to its effect. Rather he offers an alleged reductio ad absurdum of the opposing view that "'tis not absolutely necessary a cause shou'd precede its effect; but that any object or action, in the very first moment of its existence, may exert its productive quality, and give rise to another object or action, perfectly co-temporary with itself (T 1.3.2.7; SBN 76)." This careful summary Todd Ryan is Assistant Professor of Philosophy, Trinity College, Hartford, CT 06106-3100, USA. e-mail: [email protected] 30 Todd Ryan of the opposing view provides a clear statement of what Hume takes to be at issue, namely whether it is "absolutely necessary" that a cause be temporally prior to its effect. From this it can readily be inferred precisely what would count as a refutation of his own view. Specifically, if it could be shown that some objects can produce their effect perfectly contemporaneously with themselves, then his position would have to be abandoned.3 It is against this latter possibility that Hume directs his argument. He writes: 'Tis an establish'd maxim both in natural and moral philosophy, that an object, which exists for any time in its full perfection without producing another, is not its sole cause; but is assisted by some other principle, which pushes it from its state of inactivity, and makes it exert that energy, of which it was secretly possest. Now if any cause may be perfectly co-temporary with its effect, 'tis certain, according to this maxim, that they must all of them be so; since any one of them, which retards its operation for a single moment, exerts not itself at that very individual time, in which it might have operated; and therefore is no proper cause. The consequence of this wou'd be no less than the destruction of that succession of causes, which we observe in the world; and indeed, the utter annihilation of time. For if one cause were co-temporary with its effect, and this effect with its effect, and so on, 'tis plain there wou'd be no such thing as succession, and all objects must be co-existent (T 1.3.2.7; SBN 76). The general structure of the argument is reasonably clear. According to the "establish'd maxim" (hereafter EM) any object that does not produce an effect as soon as possible is not the "sole cause" of that effect. Assuming then that causes might occur simultaneously with their effects, it follows that every proper cause must be contemporaneous with its effect. But if every effect occurs simultaneously with its cause, then we arrive at the absurd conclusion that there can be no causal (or indeed temporal) succession in the world. Therefore, the original assumption that a cause may be perfectly co-temporary with its effect must be... (shrink)

In a number of papers, including the one published in this journal, Robert Sparrow has mounted attacks on consequentialism using principally what he takes to be an important fact, which he believes constitutes a reductio ad absurdum of consequentialism in its many forms and of this author's approach to enhancement and disability in particular (see page 276). This fact is the current longer life expectancy of women when compared with men. Here the author argues that Sparrow's arguments and (...) entire approach utterly fail. In doing so the author hopes to shed further light on the role of normalcy, normal species functioning and species-typical functioning in debates about enhancement and disability. (shrink)

In the Tractatus Logico‐Philosophicus, Wittgenstein adopts a version of logical atomism. This chapter offers an exposition of the Tractarian version of logical atomism. Wittgenstein argues that the constituents of the end products of complete analysis are simple signs, and that there are necessarily existent objects. The chapter explains Wittgenstein's main argument for the possibility of complete analysis. It comments on three recent interpretations of the substance argument and offers an exposition of the substance argument. According to the Tractatus, propositions show (...) the logical form of reality, which is constituted by the logical forms of states of affairs. The substance argument is a reductio ad absurdum. The reductio is the premise that the world had no substance, which is equivalent to the claim that there were no necessarily existent simple objects. The world has substance constituted by necessarily existent simple objects. (shrink)

David Lewis introduced a new kind of reductio ad absurdum style of argument: while the claims, suitably formalized, do not lead to outright contradiction, he showed they are tenable only in trivial ways. Lewis proved what are known as triviality results against the claims. The claims are "Probabilities of conditionals are conditional probabilities." "Desires are beliefs about what is good." The author argues that the tenuous connections between the claims go considerably further still: the claims give rise to (...) debates that display a remarkably parallel structure. He brings out their many similarities to illuminate both of them, and to point the way to some promising avenues for future research. He displays structural similarities between the fluctuating fortunes of Stalnaker's Thesis, and those of Desire‐as‐Belief. Lewis concludes telegraphically by saying that Desire by Necessity is "a form of anti‐Humeanism, sure enough, but not the right form of anti‐Humeanism"; and that's it. (shrink)

Don Marquis’ future-like-ours account argues that abortion is seriously immoral because itdeprives the embryo or fetus of a valuable future much like our own. Marquis was mindful ofcontraception being reductio ad absurdum of his reasoning, and argued that prior tofertilisation, there is not an identifiable subject of harm. Contra Marquis, Tomer Chaffercontends that the ovum is a plausible subject of harm, and therefore contraception deprives theovum of a future-like-ours. In response, I argue that being an identifiable subject of (...) harm is notsufficient for Marquis’ argument to succeed. In addition, we must also share our identity withan ovum. I show that on the account of personal identity utilised by Marquis’ defenders, weare not identical with an ovum. As a result, Chaffer’s reductio fails. (shrink)

Desmond Clarke's remarks on “my” absurdity argument are puzzling. i) Although I do indeed still believe it to be a valid argument, I certainly would not claim credit for it. I believe that “Reducibility: Another Side Issue?” put the general problem of the reducibility of mind into a somewhat unorthodox context, but the particular claim Clarke is attacking forms only one very unoriginal step in the general argument of that essay. ii) Some points that Clarke makes I would certainly agree (...) to, and believe I have agreed to in some of the texts he cites, while others are far from anything I meant to convey. Under Clarke's, 1) of course the “antinomies” of the paper above referred to trade on ambiguities. That's one of the points of the paper. 2) in both “Reducibility … ” and “To Have A Mind …”, I have tried to specify the sense in which “mechanism” was being used. That I do not take such terms as self-explanatory should be clear, for instance, from the remarks in the latter paper that immediately follow the passage Clarke criticizes. 3) I have no idea how physics is to develop in the future, nor did I wish to suggest that I did. With the rest of Clarke's I entirely agree. As to his, I fail to see its relevance to my argument, unless it simply leads up to and, with which, again, I wholeheartedly concur. Nancy Maull's paper, which Clarke refers to, for example, seems to me to shed great light on what used to be thought the problem of reduction; I don't see how her argument conflicts with “mine.” iii) Clarke's two “interpretations” of “my” argument are even more puzzling. The first paragraph is clear, as far as it goes. But the second is entirely murky. Perhaps I may try to reconstruct it. “The question for the scientist of a reductivist disposition in this context,” Clarke writes, “is: would it be possible to construct an alternative theory which adequately explains the same phenomena as the human sciences?” Fair enough. But apparently one is not allowed to reflect about an answer to this question. One has to wait and see if such a theory does develop. And meantime to notice that any theory by its very nature is intentional: this is to use some part of the human sciences to establish the explanatory power of all the human sciences. Is that what is meant? If so, I would reply: that the claim that theories are inherently intentional is not a thesis of any “human science” but a philosophical thesis about the nature of intelligible discourse. If a wholly non-intentional theory of human action were stated it would invalidate itself as theory. Thus, to respond to the major accusation of, we would have an answer to Clarke's question such that the question could not have been asked. What we have, then, is not a petitio but a valid reductio ad absurdum. (shrink)

This paper is a response to Haze’s brief argument for the falsity of the theory that instantial terms refer arbitrarily, proposed by Breckenridge and Magidor in 2012. In this paper, I characterise instantial terms and outline the theory of arbitrary reference; then I reconstruct Haze’s argument and contend that it fails in its purpose. Haze’s argument is supposed to be a _reductio ad absurdum:_ according to Haze, it proves that a contradiction follows from the most basic tenets of the (...) theory of arbitrary reference. I will argue, however, that the contradiction in question follows not from these tenets, but from the surreptitious use that Haze makes of a self-referential expression. I conclude, consequently, that Haze’s argument is nothing more than an illustration of the well-known fact that self-referential expressions produce paradoxical results. (shrink)

This article discusses an anomaly in the English law of reproductive liability: that is, an inconsistency between the law’s approach to wrongful life claims and its approach to cases of negligent selection of gametes or embryos in infertility treatments (the selection cases). The article begins with an account of the legal position, which brings into view the relevant inconsistency: while the law treats wrongful life claims as non- actionable, it recognises a cause of action in the selection cases, although the (...) selection cases bear a relevant resemblance to wrongful life claims. The article then considers arguments that may be invoked in an attempt to reconcile the above two strands of the law. Three of these counterarguments consist in attempts to distinguish the selection cases from wrongful life claims. It is argued that these attempts fail to reveal a valid basis for treating these situations differently. A fourth possible counterargument levels against the present analysis a charge of reductio ad absurdum. It is shown that this argument suffers from a fundamental flaw caused by confusion between different senses of the term “identity”. Finally, the article discusses possible changes to the legal position that could rectify the problem. It argues that one of these changes, which focuses on legal redress for violation of personal autonomy, is particularly apt to resolve the problem at hand, but also highlights the need for further inquiry into the broader implications of introducing this form of redress into the law of torts. (shrink)

Ibn Sīnā proposed an analysis of arguments by reductio ad absurdum. His analysis contains, perhaps for the first time, a workable method for handling the making and discharging of assumptions in a formal proof. We translate the relevant text of Ibn Sīnā and put his analysis into the context of his general approach to logic.

In this dissertation I examine the sceptical problem of rule following presented by Saul Kripke in his interpretation of Ludwig Wittgenstein's later works: Do any facts determine what rule we were following in our apparently rule-following activities such as the use of language? I distinguish three ways of understanding this question--modest scepticism, radical scepticism, and metascepticism--and address them in Parts 1, 2 and 3 of the dissertation, respectively. ;Part 1 discusses modest scepticism, which asserts that no finite facts about humans (...) can determine rules which have infinitely many possible applications. I resolve this apparent conflict between the finite and the infinite by incorporating the recursiveness of rule applications into the theory of rules. ;Part 2 discusses radical scepticism, which asserts that no facts determine what normative rules we were following. I show first that this challenge has a wider scope than the Humean Thesis of the underivability of ought from is, and that as a result, the radical sceptic can refute attitudinal theories of norms, which have been considered a possible response to the Humean challenge. I then propose a solution to radical scepticism which explains our practice and beliefs about normative rules without assuming the existence of rule-determining facts. Unlike the solution Kripke ascribes to Wittgenstein, it offers no justification of our practice and beliefs about normative rules. Some methodological implications of the solution are also explored. ;Part 3 discusses metascepticism about rule following, whose challenge extends to the rules used for the very discussion of rule following. I examine first whether such a challenge is self-undermining in that it makes the sceptical argument itself impossible. I propose an extended form of reductio ad absurdum argument by which the metasceptic can challenge rules in general, including those used in the sceptical argument. Then I argue that the solution to radical scepticism given in Part 2 survives metascepticism as well. (shrink)

Bart Streumer employs a reductio ad absurdum to show that a hyperintensional conception of properties has a multiplication problem; roughly, this conception of properties leads to the absurd result that we can multiply distinct but co-intensional properties without end. In this paper, I will explain why Streumer’s reductio fails to convince.

ABSTRACT William Hurlbut, a Stanford University bioethicist and member of the President's Council on Bioethics, recently proposed a solution to the current impasse over human embryonic stem cell research in the United States. He suggested that researchers could use genetic engineering and somatic cell nuclear transfer (i.e. cloning) to develop human ‘pseudo‐embryos’ that have no potential to develop fully into human persons. According to Hurlbut, even thinkers who typically ascribe high moral status to human embryos could approve of destroying these (...) ‘pseudo‐embryos’ for the sake of harvesting human embryonic stem cells. This essay argues, first, that an argument based on the ‘paradox of the heap’ (an argument that many ‘pro‐life’ thinkers employ in order to defend the notion that human embryos have high moral value from the moment of conception) challenges the ethical legitimacy of Hurlbut's proposal. Second, the paper argues that this conflict may illustrate a reductio ad absurdum for this ‘pro‐life’ argument itself rather than being a problem for Hurlbut's proposal. As a result, the paper challenges the ‘pro‐life’ strategy of arguing that one should respond to uncertainty about the moral status of developing embryos by being morally ‘cautious’ and granting all human embryos full moral status from the moment of conception. It appears that one is faced with a complex series of choices (about where to draw the moral line between entities that are human persons and entities that are not), and a strict moral ‘cautiousness’ about this series of choices may ultimately lead to absurdity. (shrink)

Norman Finkelstein, a prominent political scientist specializing in the Palestine-Israel conundrum, on which he has authored five highly praised books, was denied tenure at DePaul University by the President, Rev. Dennis H. Holtschneider, on June 8, 2007. After examining the particulars of the case, it strikes me as so obviously wrong to deny him tenure that the tenure procedure at DePaul constitutes a reductio ad absurdum of a university system which allows such a thing to happen.

With characteristic candour, David Hume is prepared to admit that in ordinary life, but certainly not when reflecting on the nature of perceptual experience, he has no option but to ‘believe in the existence of body’ despite his philosophical reasonings to the contrary. In this instance, his commitment to ‘Common Sense’ has become, as it was not to become for his contemporary Thomas Reid, a direct consequence of participating in a day-to-day existence if nevertheless one which he has no option (...) but to reject when reflecting in the study.Ludwig Wittgenstein, on the other hand, presents us with a picture of what has come to be regarded as a form of Humean ‘phenomenalist language’, private in nature, which, in one of the most famous passages of his later philosophy, he appears to reject via a form of reductio ad absurdum argument. In what follows, it will be questioned whether his ‘argument’ clearly represents phenomenalist proposals which Hume’s successors, e. g., A.J. Ayer, accepted without question. If there is a misunderstanding here on both sides, an investigation into its nature must lead to an appreciation of the varying roles attributed by these philosophers to the notion of ‘Common Sense’. (shrink)

Mencius, a prominent Confucian philosopher in the Warring States period of ancient China, is well-known for his argumentative skills, including his refutational skills used to maintain his own standpoints. This paper attempts to reveal how Mencius refuted his opponents argumentatively and strategically on the issue of human nature. To this end, the pragma-dialectical approach to argumentation is adopted to first reconstruct Mencius’s argumentative discourse on human nature according to the four stages in critical discussion—the confrontation, opening, argumentation and concluding stages. (...) Under the ancient Chinese historical and cultural context, Mencius’s argumentative discourse about human nature was developed in three critical discussions, between Mencius the protagonist, and his explicit interlocutors and implicit adversaries who held different views on human nature—the antagonists. The discussions were undertaken around three single mixed differences of opinion concerning three propositions, with resolution of the first difference of opinion serving as a starting point of the second, and the resolution of the second as a starting point of the third. Then based on the reconstruction, the paper elaborates the refutational strategies that Mencius employed in various stages, such as dissociation, reductio ad absurdum based on refutational analogy, and conciliation. It further points out that the employment of these strategies is strategic maneuvering undertaken by Mencius in an attempt to realize both dialectical and rhetorical aims. (shrink)

Inferential or epistemic conditional sentences represent a blueprint of someone’s reasoning process from premise to conclusion. Declerck and Reed (2001) make a distinction between a direct and an indirect type. In the latter type the direction of reasoning goes backwards, from the blatant falsehood of the consequent to the falsehood of the antecedent. We first present a modal reinterpretation in terms of Argumentation Schemes of indirect inferential conditionals (IIC’s) in Declerck and Reed (2001). We furthermore argue for a distinction between (...) epistemic-modal strong and deontic-modal weak IIC’s. In addition, we extend the category of the indirect inferential conditionals in order to include several other deontic-modal subtypes. On the basis of the undesirability of the consequent the hearer in these cases infers that the antecedent is also undesirable. In this way the rhetoric-argumentative strategy of Reductio ad Absurdum is extended from the realm of deductive reasoning to that of practical reasoning. (shrink)

I. In “Whitehead’s Theory of Becoming," V.C. Chappell asserts that Whitehead’s “epochal theory of time or becoming is both untenable and unnecessary”. It is untenable, he argues, because “ … the theory itself is unintelligible, and … … the Zenonian argument on which the theory is founded, even in its amended, Whiteheadian version, is invalid”. Although it is not clear to me that Whitehead’s use of Zeno’s arguments is unsound, our concern here will be limited to the first of these (...) two claims. I will attempt to show that Chappell’s demonstration of the unintelligibility of Whitehead’s theory begs the question. His purpose is to present us with a reductio ad absurdum of the epochal theory of time, but he succeeds only in demonstrating that if we substitute other premises for Whitehead’s own, his conclusions will not be consistent with these substitute premises. (shrink)

Arthur Cunningham has asserted that my argument targeting the “freedom problem” for Molinism is unsuccessful. I show that while he has correctly identified two minor (and correctible) problems with the argument, Cunningham’s main criticisms are ineffective. This is mainly because he has failed to appreciate the complex dialectical situation created by the use of a reductio ad absurdum argument. The result is to underscore the difficulty for Molinism of the freedom problem.

I show that what Quine calls 'pressing from above' is an argument for indeterminacy of translation that is generated by assuming the partial interpretation view of scientific theories. Furthermore, I argue that Quine's thesis should be understood as a reductio ad absurdum of partial interpretation and/or the view that the meaning of a term determines a unique extension for the term.

The article aims at elucidating the argumentation in Anselm's Proslogion by relating some aspects of it to the early medieval theory of argument. The focus of the analysis is on the "single argument" (unum argumentum), the discovery of which Anselm announces in the Preface to the Proslogion. Part 1 of the article offers a preliminary description of the single argument by describing the reductio ad absurdum technique based on the notion "that than which a greater cannot be thought". (...) Part 2 discusses the ideas about arguments and argumentation that Boethius presents in Book One of his In Ciceronis Topica. Part 3 draws attention to some early medieval sources (Abelard, Lanfranc, Anselm) that are witness to the importance of the Boethian ideas in Anselm's time. Finally, Part 4 argues that Anselm looked at his single argument in the Boethian framework and that the term "that than which a greater cannot be thought" should be identified as his single argument. (shrink)

Thomas Kuhn has argued that scientists never reject a paradigm without simultaneously accepting a new paradigm. Coupled with Kuhn's claim that it is paradigms as a whole, and not individual theories, that are accepted or rejected, this thesis is seen as one of Kuhn's main challenges to the rationality of science. I argue that Kuhn is mistaken in this claim; at least in some instances, science rejects a paradigm despite the absence of a successor. In particular, such a description best (...) fits Kuhn's most discussed example, the Copernican Revolution. By differentiating scientific discoveries into three types, spontaneous, implicit, and directed, we see that Kuhn's thesis holds for spontaneous and implicit discoveries, but not directed discoveries. Directed discoveries must be understood by an alternative account of falsifiability, based on argument by reductio ad absurdum rather than argument by modus tollens as traditional accounts of falsifiability would have it. (shrink)

Heidegger’s understanding of technology advances a conceptual critique of what he calls “the enframing” (Gestell), the epistemological and ontological presuppositions underlying technology. Reconstructing the central argument of Country Path Conversation (1945), the chapter focuses the positive contrast to “the enframing” Heidegger finds in the idea of Gelassenheit (“releasement”): releasement defines a form of life marked by an intellectual independence from technology achieved through a specific form of thinking. Drawing from Haugeland, section 1 establishes “enabling” as genuine sense of (...) the German verb lassen (to let); in contrast to the form of thinking determinative of technology, which Heidegger describes as imposing, the “released” and genuine form of human thinking is an enabling thinking. In sections 2 and 3, I reconstruct the reductio ad absurdum Heidegger uses to distance this form of thinking from forms of transcendental philosophy embracing (mediational) representationalism. In section 4, I highlight the (ontic) correlate of such thinking, namely the individual things (Dinge) manifest outside the horizon of understanding presupposed by technology. Not based on or anticipating any positive ontology, I argue that “enabling” thinking is ontologically non-committal. Section 5 contrasts this understanding of Gelassenheit with views advanced by Dreyfus, Rojcewicz, Belu, and Feenberg. (shrink)

In his logical foundation of arithmetic, Frege faced the problem that the semantic interpretation of his system does not determine the reference of the abstract terms completely. The contextual definition of number, for instance, does not decide whether the number 5 is identical to Julius Caesar. In a late writing, Quine claimed that the indeterminacy of reference established by Frege’s Caesar problem is a special case of the indeterminacy established by his proxy-function argument. The present paper aims to show that (...) Frege’s Caesar problem does not really support the conclusions that Quine draws from the proxy-function argument. On the contrary, it reveals that Quine’s argument is a non sequitur: it does not establish that there are alternative interpretations of our terms that are equally correct, but only that these terms are ambiguous. The latter kind of referential indeterminacy implies that almost all sentences of our overall theory of the world are either false or neither true nor false, because they contain definite descriptions whose uniqueness presupposition is not fulfilled. The proxy-function argument must therefore be regarded as a reductio ad absurdum of Quine’s behaviorist premise that the reference of terms is determined only by our linguistic behavior. (shrink)

What good is logic? -- Seventeen ways this book is different -- The two logics -- All of logic in two pages : an overview -- The three acts of the mind -- I. The first act of the mind : understanding -- Understanding : the thing that distinguishes man from both beast and computer -- Concepts, terms and words -- The problem of universals -- The comprehension and extension of terms -- II. Terms -- Classifying terms -- Categories -- (...) Predicables -- Division -- III. Material fallacies -- Fallacies of language -- Fallacies of diversion -- Fallacies of oversimplification -- Fallacies of argumentation -- Inductive fallacies -- Procedural fallacies -- Metaphysical fallacies -- Short story : love is a fallacy -- IV. Definition -- The nature of definition -- The rules of definition -- The kinds of definition -- The limits of definition -- V. Second act of the mind : judgment -- Judgments, propositions, and sentences -- What is truth? -- The four kinds of categorical propositions -- Logical form -- Euler's circles -- Tricky propositions -- The distribution of terms -- VI. Changing propositions -- Immediate inference -- Conversion -- Obversion -- Contraposition -- VII. Contradiction -- What is contradiction? -- The square of opposition -- Existential import -- Tricky propositions on the square -- Some practical uses of the square of opposition -- VIII. The third act of the mind : reasoning -- What does reason mean? -- The ultimate foundations of the syllogism -- How to detect arguments -- Arguments vs. explanations -- Truth and validity -- IX. Different kinds of arguments -- Three meanings of because -- The four causes -- A classification of arguments -- Simple argument maps -- Deductive and inductive arguments -- Combining deduction and induction : socratic method -- X. Syllogisms -- The structure and strategy of the syllogism -- The skeptics objection to the syllogism -- The empiricist's objection to the syllogism -- Demonstrative syllogisms -- How to construct convincing syllogisms -- XI. Checking syllogisms for validity -- By Euler's circles -- By Aristotle's six rules -- Barbara Celarent : mood and figure -- Venn diagrams -- XII. More difficult syllogisms -- Enthymemes : abbreviated syllogisms -- Sorites : chain syllogisms -- Epicheiremas : multiple syllogisms -- Complex argument maps -- XIII. Compound syllogisms -- Hypothetical syllogisms -- Reductio ad absurdum arguments -- The practical syllogism : arguing about means and ends -- Disjunctive syllogisms -- Conjunctive syllogisms -- Dilemmas -- XIV. Induction -- What is induction? -- Generalization -- Causal induction : Mill's methods -- Scientific hypotheses -- Statistical probability -- Arguments from analogy -- A fortiori and a minore arguments -- XV. Some practical applications of logic -- How to write a logical essay -- How to write a socratic dialogue -- How to have a socratic debate -- How to use socratic method on difficult people -- How to read a book socratically -- XVI. Some philosophical applications of logic -- Logic and theology -- Logic and metaphysics -- Logic and cosmology -- Logic and philosophical anthropology -- Logic and epistemology -- Logic and ethics. (shrink)

In this paper, I consider a popular version of the clever student’s reasoning in the surprise examination case, and demonstrate that a valid argument can be constructed. The valid argument is a reductio ad absurdum with the proposition that the student knows on the morning of the first day that the teacher’s announcement is fulfilled as its reductio. But it would not give rise to any paradox. In the process, I criticize Saul Kripke’s solution and Timothy Williamson’s (...) attack on a key step of the student’s reasoning. I then consider the condemned prisoner case in W. V. Quine’s paper ‘On a So-Called Paradox’. I argue that the prisoner’s reasoning as conceived by Quine is more relevant and reasonable than the student’s argument in the popular version of the surprise examination case. I also argue that Quine’s criticism of the prisoner’s reasoning is correct, and therefore that the condemned prisoner case, and the surprise examination case as well, would not generate any paradox. (shrink)

The article is a reductio ad absurdum of assumptions which are shared by a large number of followers of the animal welfare movement and utilitarianism. I argue that even if we accept the main ethical arguments for a negative moral assessment of eating meat we should not promote vegetarianism but rather beefism (eating only meat from beef cattle). I also argue that some forms of vegetarianism, i.e. ichtivegetarianism, can be much more morally worse than normal meat diet. In (...) order to justify these thesis I show that there are significant moral differences in the consumption of animal products from different species. (shrink)

Pacifists imagine a “great peace,” to borrow a phrase from Martin Buber. This great peace will uphold justice and respect for humanity. It will not efface difference or negate liberty and identity. The great peace will be a space in which genuine dialogue can flourish—in which we can encounter one another as persons, listen to one another, embrace our common humanity, and acknowledge our differences. The great peace is much more than the absence of war. It is holistic, organic, dialogical, (...) and thick with human relation.The dream of the great peace runs aground on the reality of petty conflicts, dehumanizing institutions, selfishness, egoism, arrogance, murder, war, and psychopathology. While ordinary selfishness poses a mundane obstacle to the great peace, genocide appears to create a reductio ad absurdum argument against the dream of the great peace and against pacifism itself. Critics will argue that in extremis a pacifist would be either mad or immoral to remain committed to nonviolence. This idea has been explored by a number of critics who argue that pacifism is primarily for dreamers and idealists, who are not willing to do what is necessary to confront evil and atrocity in the real world.This paper argues that a moderate commitment to pacifism and nonviolence remains plausible despite the atrocity objection. Some may argue that the term “pacifism” is not applicable to a position that admits that there are exceptional cases in which violence can be justified. But as I have argued elsewhere, there are varieties of pacifism (Fiala, 2004; 2008; 2014a; 2014b). The type of pacifism described here is transformational or transformative pacifism. Transformational pacifism is not absolutist in its rejection of violence, even though it offers a comprehensive critique of violence that aims at creating the great peace by changing the way we think and talk about war, violence, and peace itself. Martin Buber is a good example of a transformational pacifist. He admitted that some form of violence could be justified (say, in response to the Holocaust). But his goal was not to justify violence—rather, he wanted to transform the world in order to prepare the way for the great peace. One important consideration here is that Buber is not primarily a political thinker or an applied ethicist: rather, he offers a metaphysical, religious, psychological, and cultural theory. Transformative pacifism is located at that higher level. It idealizes, speculates, and imagines. For this reason, critics might condemn it as utopian. But trans-formative pacifism remains inspiring and useful. (shrink)

We study how to postpone the application of the reductio ad absurdum rule (RAA) in classical natural deduction. This technique is connected with two normalization strategies for classical logic, due to Prawitz and Seldin, respectively. We introduce a variant of Seldin’s strategy for the postponement of RAA, which induces a negative translation from classical to intuitionistic and minimal logic. Through this translation, Glivenko’s theorem from classical to intuitionistic and minimal logic is proven.

Arthur Cunningham has asserted that my argument targeting the “freedom problem” for Molinism is unsuccessful. I show that while he has correctly identified two minor (and correctible) problems with the argument, Cunningham’s main criticisms are ineffective. This is mainly because he has failed to appreciate the complex dialectical situation created by the use of a reductio ad absurdum argument. The result is to underscore the difficulty for Molinism of the freedom problem.

David Chalmers' dancing qualia argument is intended to show that phenomenal experiences, or qualia, are organizational invariants. The dancing qualia argument is a reductio ad absurdum, attempting to demonstrate that holding an alternative position, such as the famous inverted spectrum argument, leads one to an implausible position about the relation between consciousness and cognition. In this paper, we argue that Chalmers' dancing qualia argument fails to establish the plausibility of qualia being organizational invariants. Even stronger, we will argue (...) that the gap in the argument cannot be closed. (shrink)