This book provides a practical and accessible way of evaluating good and bad arguments used in everyday conversations by applying normative models of dialectical (interactive) argumentation, where two parties reason together in an orderly and cooperative way. Using case studies, the author analyzes correct and incorrect uses of argumentation on controversial issues that engage the reader's interest while illustrating points in a practical way. Walton gives clear explanations of the most common errors and tricky deceptions -- traditionally called "fallacies" -- (...) that can trip up an unwary arguer. (shrink)

In this paper we argue that in recent literature on mechanistic explanations, authors tend to conflate two distinct features that mechanistic models can have or fail to have: plausibility and richness. By plausibility, we mean the probability that a model is correct in the assertions it makes regarding the parts and operations of the mechanism, i.e., that the model is correct as a description of the actual mechanism. By richness, we mean the amount of detail the model gives (...) about the actual mechanism. First, we argue that there is at least a conceptual reason to keep these two features distinct, since they can vary independently from each other: models can be highly plausible while providing almost no details, while they can also be highly detailed but plainly wrong. Next, focusing on Craver's continuum of ?how-possibly,? to ?how-plausibly,? to ?how-actually? models, we argue that the conflation of plausibility and richness is harmful to the discussion because it leads to the view that both are necessary for a model to have explanatory power, while in fact, richness is only so with respect to a mechanism's activities, not its entities. This point is illustrated with two examples of functional models. (shrink)

Counterfactual thinking involves imagining hypothetical alternatives to reality. Philosopher David Lewis argued that people estimate the subjective plausibility that a counterfactual event might have occurred by comparing an imagined possible world in which the counterfactual statement is true against the current, actual world in which the counterfactual statement is false. Accordingly, counterfactuals considered to be true in possible worlds comparatively more similar to ours are judged as more plausible than counterfactuals deemed true in possible worlds comparatively less similar. Although (...) Lewis did not originally develop his notion of comparative similarity to be investigated as a psychological construct, this study builds upon his idea to empirically investigate comparative similarity as a possible psychological strategy for evaluating the perceived plausibility of counterfactual events. More specifically, we evaluate judgments of comparative similarity between episodic memories and episodic counterfactual events as a factor influencing people's judgments of plausibility in counterfactual simulations, and we also compare it against other factors thought to influence judgments of counterfactual plausibility, such as ease of simulation and prior simulation. Our results suggest that the greater the perceived similarity between the original memory and the episodic counterfactual event, the greater the perceived plausibility that the counterfactual event might have occurred. While similarity between actual and counterfactual events, ease of imagining, and prior simulation of the counterfactual event were all significantly related to counterfactual plausibility, comparative similarity best captured the variance in ratings of counterfactual plausibility. Implications for existing theories on the determinants of counterfactual plausibility are discussed. (shrink)

In this chapter I defend a methodological view about how we should conduct substantive ethical inquiries in the fields of normative and practical ethics. I maintain that the direct plausibility and implausibility of general ethical principles – once fully clarified and understood – should be foundational in our substantive ethical reasoning. I argue that, in order to expose our ethical intuitions about particular cases to maximal critical scrutiny, we must determine whether they can be justified by directly plausible principles. (...) To expose apparently plausible principles to maximal critical scrutiny, we must determine whether their direct plausibility can survive careful clarification of what they are really saying. This means that intuitions about cases are useful only in (a) suggesting principles that must stand on their own two feet, and (b) illustrating or otherwise helping us clarify what a principle is really saying. We should not reject principles that seem most directly plausible after we have fully clarified their content simply because they conflict with our intuitions about cases, because to do so is to side with uncritical prejudices over the teachings of critical scrutiny. (shrink)

Abstract. Richard Feldman’s Uniqueness Thesis holds that “a body of evidence justifies at most one proposition out of a competing set of proposi- tions”. The opposing position, permissivism, allows distinct rational agents to adopt differing attitudes towards a proposition given the same body of evidence. We assess various motivations that have been offered for Uniqueness, including: concerns about achieving consensus, a strong form of evidentialism, worries about epistemically arbitrary influences on belief, a focus on truth-conduciveness, and consequences for peer disagreement. (...) We argue that each of these motivations either misunderstands the commitments of permissivism or is question-begging. Better understanding permissivism makes it a much more plausible position. (shrink)

The national-level scenarios project NanoFutures focuses on the social, political, economic, and ethical implications of nanotechnology, and is initiated by the Center for Nanotechnology in Society at Arizona State University (CNS-ASU). The project involves novel methods for the development of plausible visions of nanotechnology-enabled futures, elucidates public preferences for various alternatives, and, using such preferences, helps refine future visions for research and outreach. In doing so, the NanoFutures project aims to address a central question: how to deliberate the social implications (...) of an emergent technology whose outcomes are not known. The solution pursued by the NanoFutures project is twofold. First, NanoFutures limits speculation about the technology to plausible visions. This ambition introduces a host of concerns about the limits of prediction, the nature of plausibility, and how to establish plausibility. Second, it subjects these visions to democratic assessment by a range of stakeholders, thus raising methodological questions as to who are relevant stakeholders and how to activate different communities so as to engage the far future. This article makes the dilemmas posed by decisions about such methodological issues transparent and therefore articulates the role of plausibility in anticipatory governance. (shrink)

Amyloid beta precursor protein (APP) and prion protein (PrP) are cell membrane elements implicated in neurodegenerative diseases. Both proteins undergo endoproteolysis. Evidence is adduced from the literature hinting that the process in the two proteins could be related, their functions may overlap and their distributions coincide. It is proposed that PrP catalyses its own cleavage, the C-terminal fragment functions as an α secretase and the N-terminal segment chaperones the active site; the α secretase releases anticoagulant and neurotrophic ectodomains from APP. (...) The proposals explain some features of spongiform encephalopathies. BioEssays 23:456–462, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

Several approaches to implementing symbol-like representations in neurally plausible models have been proposed. These approaches include binding through synchrony, “mesh” binding, and conjunctive binding. Recent theoretical work has suggested that most of these methods will not scale well, that is, that they cannot encode structured representations using any of the tens of thousands of terms in the adult lexicon without making implausible resource assumptions. Here, we empirically demonstrate that the biologically plausible structured representations employed in the Semantic Pointer Architecture approach (...) to modeling cognition do scale appropriately. Specifically, we construct a spiking neural network of about 2.5 million neurons that employs semantic pointers to successfully encode and decode the main lexical relations in WordNet, which has over 100,000 terms. In addition, we show that the same representations can be employed to construct recursively structured sentences consisting of arbitrary WordNet concepts, while preserving the original lexical structure. We argue that these results suggest that semantic pointers are uniquely well-suited to providing a biologically plausible account of the structured representations that underwrite human cognition. (shrink)

While the theory of relative plausibility is presented by Allen and Pardo as a descriptive theory of the proof process, this commentary discusses their theory as a possible starting point for a prescriptive theory of evidence assessment. Generally, naturalness and simplicity are necessary for the success of such a theory. The theory of relative plausibility is very promising in this respect, as its key concept is the straightforward and intuitive notion of explanation, according to which an explanation is (...) an answer to a “why” question. Still, both the explanatory and the comparative dimensions of relative plausibility are in need of elaboration if one wants to give advice on evidence assessment in terms of Allen and Pardo’s framework. For one thing, it is necessary to examine the epistemological status of the various explanatory criteria regarding their potential as guides to truth or likelihood. Only epistemic criteria should be included in recommendations to fact-finders. Moreover, given the author’s interpretation of the ‘beyond any reasonable doubt’ standard, it is unclear what the comparative dimension amounts to in criminal trials. At least a comparison of the kind involved in the author's account of civil trials standards is absent in their interpretation of BARD. If the comparative dimension of relative plausibility is relevant at all in criminal trials, it must be clarified what is to be compared. (shrink)

In this article, I present a defense of conceptual plausibility, understood as an epistemic way to qualify concepts that situates them between the merely possible and the actual. To show that there is such a thing as conceptual plausibility, I rely on what seems to lie at the heart of many uses of the phrase “plausible concept”: explanatory fruitfulness. To make an effective case for the claim that conceptual plausibility is of philosophical interest, I present an argument (...) based on the debate over the rationality of theistic belief and the concept of God. To show that conceptual plausibility is philosophically feasible, I first show that it cannot be reduced to propositional plausibility. Next, I offer a minimally precise characterization of conceptual plausibility; I approach this from a qualitative and comparative perspective as well. Finally, I show how these qualitative and comparative criteria of conceptual plausibility might be applied to the debate over the rationality of theistic belief and the concept of God. (shrink)

The United States Supreme Court's decision in Bell Atlantic Corp. v. Twombly is creating quite a stir. Suddenly gone is the famous loosey-goosey rule of Conley v. Gibson that a complaint should not be dismissed for failure to state a claim unless it appears beyond doubt that the plaintiff can prove no set of facts in support of his claim which would entitle him to relief.Now a complaint must provide enough facts to state a claim to relief that is plausible (...) on its face. Only decided last May, Bell Atlantic has been cited in over 3,700 cases. Already being described as a landmark decision, Bell Atlantic nonetheless has lawyers and judges scratching their heads over the precise pleading standard to apply in its wake. As the Second Circuit (mildly) put it, Considerable uncertainty concerning the standard for assessing the adequacy of pleadings has recently been created by the Supreme Court's decision in Bell Atlantic Corp. v. Twombly. Just what is a plausible showing that the pleader is entitled to relief under Rule 8(a)(2)?I believe an answer lies in the 26-year-old decision of the Former Fifth Circuit in In re Plywood Antitrust Litigation. Plywood Antitrust requires, at a minimum, that a complaint . . . contain either direct or inferential allegations respecting all the material elements necessary to sustain a recovery under some viable legal theory. Already used in more than half the circuits, this standard paraphrases advice found in the venerable WRIGHT & MILLER for nearly 40 years.Properly applied, this all . . . material elements standard satisfies Bell Atlantic's plausibility requirement in all respects. The Plywood Antitrust pleading standard works well after Bell Atlantic, first, because the Supreme Court referred to the standard, albeit parenthetically, with approval in Bell Atlantic. Second, it does much to harmonize the Federal Rules' goal of dispensing with pleading technicalities while still requiring enough general factual information about a pleader's claim to make the notice in notice pleading meaningful. Finally, and perhaps most importantly, it gives lawyers, litigants, and courts a standard they can actually use when drafting, or assessing the sufficiency of, pleadings. (shrink)

This note discusses three issues that Allen and Pardo believe to be especially problematic for a probabilistic interpretation of standards of proof: (1) the subjectivity of probability assignments; (2) the conjunction paradox; and (3) the non-comparative nature of probabilistic standards. I offer a reading of probabilistic standards that avoids these criticisms.

In this article, a qualitative notion of subjective plausibility and its revision based on a preorder relation are implemented in higher-order logic. This notion of plausibility is used for modeling pragmatic aspects of communication on top of traditional two-dimensional semantic representations.

Possibilities haunt history. The force of our explanations of events turns on the alternative possibilities these explanations suggest. It is these possible worlds which give us our understanding; and in human affairs we decide them by practical rather than theoretical judgement. In his widely acclaimed account of the role of counterfactuals in explanation, Geoffrey Hawthorn deploys extended examples from history and modern times to defend his argument. His conclusions cast doubt on existing assumptions about the nature and place of theory, (...) and indeed of the possibility of knowledge itself, in the human sciences. (shrink)

Recent work by Marchisella exposed a gap in the literature on causal non-monotonic reasoning: what is needed is an approach whose primary motivation is the formal representation of the way in which humans typically reason with cause and effect. We extend the work of Marchisella, and propose a new type of causal non-monotonic reasoning, _Plausible Causal Reasoning_, which fills the gap in the literature. We propose some new principles which help characterise Plausible Causal Reasoning, and suggest a family of non-monotonic (...) logics which provides a suitable starting point for its formalisation. (shrink)

The plausible reasoning class (called the JSM-reasoning in honour of John Stuart Mill) is described. It implements interaction of three forms of non-deductive procedures  induction, analogy and abduction. Empirical induction in the JSM-reasoning is the basis for generation of hypotheses on causal relations (determinants of social behaviour). Inference by analogy means that predictions about previously unknown properties of objects (individual’s behaviour) are inferred from causal relations. Abductive inference is performed to check on the explanatory adequacy of generated hypotheses. To (...) recognize rationality of respondents’ opinion deductive inference is used. Plausible reasoning, semantics of argumentation logic and deductive recognition of opinion rationality represent logical tool for cognitive sociology problems. (shrink)

In this paper it is shown how plausible reasoning of the kind illustrated in the ancient Greek example of the weak and strong man can be analyzed and evaluated using a procedure in which the pro evidence is weighed against the con evidence using formal, computational argumentation tools. It is shown by means of this famous example how plausible reasoning is based on an audience’s recognition of situations of a type they are familiar with as normal and comprehensible in their (...) shared common knowledge. The paper extends previous work on this example by using three new multiagent argumentation schemes closely related to the scheme for argument from negative consequences. (shrink)

We construct a Hilbert style system RPL for the notion of plausibility measure introduced by Halpern J, and we prove the soundness and completeness with respect to a neighborhood style semantics. Using the language of RPL, we demonstrate that it can define well-studied notions of necessity, conditionals and propositional identity.

Events that violate the laws of nature are, by definition, impossible, but recent research suggests that people view some violations as “more impossible” than others. When evaluating the difficulty of magic spells, American adults are influenced by causal considerations that should be irrelevant given the spell’s primary causal violation, judging, for instance, that it would be more difficult to levitate a bowling ball than a basketball even though weight should no longer be a consideration if contact is no longer necessary (...) for support. In the present study, we sought to test the generalizability of these effects in a non-Western context – China – where magical events are represented differently in popular fiction and where reasoning styles are often more holistic than analytic. Across several studies, Chinese adults showed the same tendency as American adults to honor implicit causal constraints when evaluating the plausibility of magical events. These findings suggest that graded notions of impossibility are shared across cultures, possibly because they are a byproduct of causal knowledge. (shrink)

2014 Reprint of 1954 American Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. This two volume classic comprises two titles: "Patterns of Plausible Inference" and "Induction and Analogy in Mathematics." This is a guide to the practical art of plausible reasoning, particularly in mathematics, but also in every field of human activity. Using mathematics as the example par excellence, Polya shows how even the most rigorous deductive discipline is heavily dependent on techniques of guessing, inductive (...) reasoning, and reasoning by analogy. In solving a problem, the answer must be guessed at before a proof can be given, and guesses are usually made from a knowledge of facts, experience, and hunches. The truly creative mathematician must be a good guesser first and a good prover afterward; many important theorems have been guessed but no proved until much later. In the same way, solutions to problems can be guessed, and a god guesser is much more likely to find a correct solution. This work might have been called "How to Become a Good Guesser."-From the Dust Jacket. (shrink)

Although, when first introduced, Copernicus's theory considered as a whole was not superior to the Ptolemaic theory according to any of the usual criteria for comparing theories and determining their acceptability, it did have features which provided the early Copernicans with good reasons for entertaining it and trying to develop it further. These features are discussed and then three plausibility considerations which seem to be operative in this case are formulated.

While Aristotle is often lauded, especially by virtue ethicists, for his focus on and insight into virtue, a central aspect of his conception of virtue—the doctrine of the mean—is often derided as false if not indeed absurd. The reason for this disparity in reaction to Aristotle is that the doctrine of the mean has been severely misinterpreted as stating that there are a variety of parameters in which one must achieve a mean. Such a doctrine is false, but it is (...) not Aristotle’s. In this paper, the author gives a more accurate account of the doctrine of the mean than has heretofore been given. According to this account, the doctrine simply states that virtue disposes one to feel one’s passions with an appropriate intensity. The author closes by considering Hursthouse’s famous criticisms of the doctrine of the mean, and he shows that they fail to be reasons for rejecting the doctrine. (shrink)

The ArgumentThis paper introduces the notion of plausibility as a decisive condition for the acceptance by groups in society of fundamental ideas concerning the nature of illness.Plausibility, it is argued, helps to explain both transition from one system of fundamental ideas to another in history, and coexistence of different such systems in a single civilization. Hence this paper challenges an interpretation of medicine prevalent, especially in medical anthropology, since the 1940s, when Erwin Ackerknecht introduced the idea of medicine (...) as an integrated aspect of a society's or community's culture.Because early research focused on small-scale communities where a majority, if not all, of the members adhered to one world view and experienced one and the same existential environment, medicine came to be identified as a cultural system representative of entire communities and, later, societies. Hence we speak of Chinese medicine as if there were one system of therapeutic ideas and practices representative of China as a whole. The fact is that even though medicine is indeed a cultural system, it is representative only of the culture developed by people sharing identical environments and experiences. That is, if within one civilization different groups coexist in different existential realities entailing different notions of what causes crisis and how to maintain harmony, then these groups will believe in different systems of ideas concerning the generation, treatment, and prevention of illness. Such systems of ideas are therefore always metaphorical reflections of a real social environment or ideas are therefore always metaphorical reflections of a real social environment or of one aspired to.It is not truth that leads to an acceptance of basic therapeutic ideas but plausibility. (shrink)

Is it possible to combine different logics into a coherent system with the goal of applying it to specific problems so that it sheds some light on foundational aspects of those logics? These are two of the most basic issues of combining logics. Paranormal modal logic is a combination of paraconsistent logic and modal logic. In this paper, I propose two further combinatory developments, focusing on each one of these two issues. On the foundational side, I combine paranormal modal logic (...) with normal modal logic, resulting into a paraconsistent and paracomplete multimodal logic dealing with the notions of plausibility and certainty. On the application side, I combine this logic with Reiter’s default logic, resulting into an inductive and consequently nonmonotonic paraconsistent and paracomplete logic able to represent some key inductive principles. (shrink)

There seems to be something wrong with passing moralistic judgments on others’ moral character. Immanuel Kant’s ethics provides insight into an underexplored way in which moralistic judgments are problematic, namely, that they are both a sign of fundamentally poor character in the moralistic person herself and an obstacle to that person’s own moral self-improvement. Kant’s positions on these issues provide a basically compelling argument against moralistic judgment of others, an argument that can be detached from the most controversial elements of (...) Kantian ethics to stand as plausible and instructive in its own right. (shrink)

The combination in the “succession narrative” of completely plausible candor about the human and confidence in the sovereign involvement of the Lord, poses the question of providence in the most profound way possible.

The cardinality of incompatible possibilities whose actuality requires at least N seconds exceeds the cardinality of disjoint intervals at least N seconds long. Therefore, not all logical possibilities can be actual in the long run, even if the long run is infinite.

Satisficing without thereby maximizing is rational provided that non-consequentialism is rational and provided that the preferred characterization of non-consequentialism is not one in which right action is justified in virtue of maximizing agent-relative value. Rather, the non-consequentialism which can serve to defend satisficing should be one in which the best characterization of certain reasons to act does not involve maximization of value of any sort, whether agent-relative or agent neutral. I argue there are reasons to prefer this sort of non-consequentialism (...) to theories which defend non-consequentialism by construing value as agent-relative. An upshot is that satisficing cannot be well-defended within an overall consequentialist framework. (shrink)

Nowadays, protecting trust in social sciences also means engaging in open community dialogue, which helps to safeguard robustness and improve efficiency of research methods. The combination of open data, open review and open dialogue may sound simple but implementation in the real world will not be straightforward. However, in view of Begley and Ellis’s (2012) statement that, “the scientific process demands the highest standards of quality, ethics and rigour,” they are worth implementing. More importantly, they are feasible to work on (...) and likely will help to restore plausibility to social sciences research. Therefore, I feel it likely that the triplet of open data, open review and open dialogue will gradually emerge to become policy requirements regardless of the research funding source. (shrink)

We present a simple propositional proof system which consists of a single axiom schema and a single rule, and use this system to construct a sequence of combinatorial tautologies that, when added to any Frege system, p-simulates extended-Frege systems.

Judgments of plausibility involve appearance of the truth or reasonableness, which is always a function of background knowledge. What anyone will countenance is conditioned by what they already know (or think they know). Marc Kirschner (professor of systems biology at Harvard) and John Gerhart (professor of molecular and cell biology at the University of California—Berkeley) aim to show that molecular, cellular, and developmental processes relevant to the generation of phenotypic variation in anatomy, physiology, and behavior demonstrate how evolutionary processes, (...) especially the origins of novelty, are plausible. The outstanding question for Kirschner and Gerhart concerns not the modification of structures but their origination—a question unanswered by the theoretical framework of the modern synthesis. (shrink)

In their unifying theory to model uncertainty, Friedman and Halpern (1995–2003) applied plausibility measures to default reasoning satisfying certain sets of axioms. They proposed a distinctive condition for plausibility measures that characterizes “qualitative” reasoning (as contrasted with probabilistic reasoning). A similar and similarly fundamental, but more general and thus stronger condition was independently suggested in the context of “basic” entrenchment-based belief revision by Rott (1996–2003). The present paper analyzes the relation between the two approaches to formalizing basic notions (...) of plausibility as used in qualitative default reasoning. While neither approach is a special case of the other, translations can be found that elucidate their relationship. I argue that Rott’s notion of plausibility allows for a more modular set-up and has a better philosophical motivation than that of Friedman and Halpern. (shrink)

How is it that a speaker _S_ can at once make it obvious to an audience _A_ that she intends to communicate some proposition _p_, and yet at the same time retain plausible deniability with respect to this intention? The answer is that _S_ can bring it about that _A_ has a high justified credence that ‘_S_ intended _p_’ without putting _A_ in a position to know that ‘_S_ intended _p_’. In order to achieve this _S_ has to exploit a (...) sense in which communication can be lottery-like. After defending this view of deniability I argue that it compares favorably to a rival account recently developed by Dinges and Zakkou (Mind, https://doi.org/10.1093/mind/fzac056, 2023 ). (shrink)

The problem adressed in this paper is “the main epistemic problem concerning science”, viz. “the explication of how we compare and evaluate theories [...] in the light of the available evidence” (van Fraassen 1983, 27).

It is well known that in his later years Gödel turned to a systematic reading of phenomenology, whose founder, Edmund Husserl, was highly esteem as a philosopher who sought to elevate philosophy to the standards of a rigorous science. For reasons purportedly related to his earlier attraction to Leibnizian monadology, Gödel was particularly interested in Husserl's transcendental phenomenology and the way it may shape the discussion on the nature of mathematical‐logical objects and the meaning and internal coherence of primitive terms (...) in mathematics. This article, which is less interested in historical facts that are amply presented in other scholars’ accounts, rather tries to point to the mostly indirect influence that the ideas of transcendental phenomenology, including Gödel's reported reference to the notion of (inner) time, had on his philosophy of mathematics, especially with a view to key independent questions of mathematical foundations. A main source for Gödel's philosophical‐epistemological views (of course in addition to his own published material) will be his recorded discussions with H. Wang and S. Toledo, as well as various articles and drafts found in his Nachlass. (shrink)