Everyday life reasoning and argumentation is defeasible and uncertain. I present a probability logic framework to rationally reconstruct everyday life reasoning and argumentation. Coherence in the sense of de Finetti is used as the basic rationality norm. I discuss two basic classes of approaches to construct measures of argument strength. The first class imposes a probabilistic relation between the premises and the conclusion. The second class imposes a deductive relation. I argue for the second class, as the first (...) class is problematic if the arguments involve conditionals. I present a measure of argument strength that allows for dealing explicitly with uncertain conditionals in the premise set. (shrink)

In this article, we argue for the general importance of normative theories of argument strength. We also provide some evidence based on our recent work on the fallacies as to why Bayesian probability might, in fact, be able to supply such an account. In the remainder of the article we discuss the general characteristics that make a specifically Bayesian approach desirable, and critically evaluate putative flaws of Bayesian probability that have been raised in the argumentation literature.

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)

We argue that Cohen’s concept of inductive or ampliative probability facilitates proper explication of sufficient strength for non-demonstrative arguments conforming to the Toulmin model. The data and claims of such arguments are singular statements. We may epistemically classify the warrants of such arguments as empirical (either physical or personal), institutional, or evaluative. Backing evidence and rebutting considerations vary with the epistemic type of warrant, but in each case the notion of ampliative probability for arguments with warrants of that type (...) can be characterized. We may then use ampliative probability to define sufficient strength and related notions for Toulmin arguments. (shrink)

Bipolar argument graphs represent the structure of complex pro and contra arguments for one or more standpoints. In this article, ampliative and exclusionary principles of evaluating argument strength in bipolar acyclic argumentation graphs are laid out and compared to each other. Argument chains, linked arguments, link attackers and supporters, and convergent arguments are discussed. The strength of conductive arguments is also addressed but it is argued that more work on this type of argument is (...) needed to properly distinguish argument strength from more general value-based components of such arguments. The overall conclusion of the article is that there is no justifiably unique solution to the problem of argument strength outside of a particular epistemological framework. (shrink)

We present a formal measure of argument strength, which combines the ideas that conclusions of strong arguments are (i) highly probable and (ii) their uncertainty is relatively precise. Likewise, arguments are weak when their conclusion probability is low or when it is highly imprecise. We show how the proposed measure provides a new model of the Ellsberg paradox. Moreover, we further substantiate the psychological plausibility of our approach by an experiment (N = 60). The data show that the (...) proposed measure predicts human inferences in the original Ellsberg task and in corresponding argument strength tasks. Finally, we report qualitative data taken from structured interviews on folk psychological conceptions on what argument strength means. (shrink)

Being able to discriminate poorly justified from well justified arguments is necessary for informed citizenship. However, it is not known whether the ability to recognize argument strength generalizes across different types of arguments, and what cognitive factors predict this ability or these abilities. Drawing on the theory of argument schemes, we examined arguments from consequence, analogy, symptoms, and authority in order to cover all major types of arguments. A study (_N_ = 278) on the general population in (...) Finland indicated that the ability to discriminate between strong and weak arguments did not differ between these schemes. Argument strength discrimination ability correlated positively with analytic thinking dispositions promoting both quality and quantity of thinking, slightly positively with education, and negatively with overconfidence. It was unrelated to an intuitive thinking style, and to self-rated mental effort. (shrink)

This work formalizes an informant-based structured argumentation approach in a multi-agent setting, where the knowledge base of an agent may include information provided by other agents, and each piece of knowledge comes attached with its informant. In that way, arguments are associated with the set of informants corresponding to the information they are built upon. Our approach proposes an informant-based notion of argument strength, where the strength of an argument is determined by the credibility of its (...) informant agents. Moreover, we consider that the strength of an argument is not absolute, but it is relative to the resolution of the conflicts the argument is involved in. In other words, the strength of an argument may vary from one context to another, as it will be determined by comparison to its attacking arguments (respectively, the arguments it attacks). Finally, we equip agents with the means to express reasons for or against the consideration of any piece of information provided by a given informant agent. Consequently, we allow agents to argue about the arguments’ strength through the construction of arguments that challenge (respectively, defeat) or are in favour of their informant agents. (shrink)

This work formalizes an informant-based structured argumentation approach in a multi-agent setting, where the knowledge base of an agent may include information provided by other agents, and each piece of knowledge comes attached with its informant. In that way, arguments are associated with the set of informants corresponding to the information they are built upon. Our approach proposes an informant-based notion of argument strength, where the strength of an argument is determined by the credibility of its (...) informant agents. Moreover, we consider that the strength of an argument is not absolute, but it is relative to the resolution of the conflicts the argument is involved in. In other words, the strength of an argument may vary from one context to another, as it will be determined by comparison to its attacking arguments (respectively, the arguments it attacks). Finally, we equip agents with the means to express reasons for or against the consideration of any piece of information provided by a given informant agent. Consequently, we allow agents to argue about the arguments’ strength through the construction of arguments that challenge (respectively, defeat) or are in favour of their informant agents. (shrink)

Different approaches analyze the strength of a natural language argument in different ways. This paper contrasts the dialectical, structural, probabilistic (or Bayesian), computational, and empirical approaches by exemplarily applying them to a single argumentative text (Epicureans on Squandering Life; Aikin & Talisse, 2019). Rather than pitching these approaches against one another, our main goal is to show the room for fruitful interaction. Our focus is on a dialectical analysis of the squandering argument as an argumentative response that (...) voids an interlocutor’s right to assertion. This analysis addresses the pragmatic dimensions of arguing and implies an argument structure that is consistent with empirical evidence of perceived argument strength. Results show that the squandering argument can be evaluated as a (non-fallacious) ad hominem argument, which however is not necessarily stronger than possible arguments attacking it. (shrink)

We reported a series of experiments carried out to confront the underlying intuitions of value-based argumentation frameworks (VAFs) with the intuitions of ordinary people. Our goal was twofold. On the one hand, we intended to test VAF as a descriptive theory of human argument evaluations. On the other, we aimed to gain new insights from empirical data that could serve to improve VAF as a normative model. The experiments showed that people’s acceptance of arguments deviates from VAF’s semantics and (...) is rather correlated with the importance given to the promoted values, independently of the perceptions of argument interactions through attacks and defeats. Furthermore, arguments were often perceived as promoting more than one value with different relative strengths. Individuals’ analyses of scenarios were also affected by external factors such as biases and arguments not explicit in the framework. Finally, we confirmed that objective acceptance, that is, the acceptance of arguments under any order of the values, was not a frequent behavior. Instead, participants tended to accept only the arguments that promoted the values they subscribe. (shrink)

Everyday reasoning requires more evidence than raw data alone can provide. We explore the idea that people can go beyond this data by reasoning about how the data was sampled. This idea is investigated through an examination of premise non‐monotonicity, in which adding premises to a category‐based argument weakens rather than strengthens it. Relevance theories explain this phenomenon in terms of people's sensitivity to the relationships among premise items. We show that a Bayesian model of category‐based induction taking premise (...) sampling assumptions and category similarity into account complements such theories and yields two important predictions: First, that sensitivity to premise relationships can be violated by inducing a weak sampling assumption; and second, that premise monotonicity should be restored as a result. We test these predictions with an experiment that manipulates people's assumptions in this regard, showing that people draw qualitatively different conclusions in each case. (shrink)

We present a novel argumentation-based method for finding and analyzing communities in social media on the Web, where a community is regarded as a set of supported opinions that might be in conflict. Based on their stance, we identify argumentative coalitions to define them; then, we apply a similarity-based evaluation method over the set of arguments in the coalition to determine the level of cohesion inherent to each community, classifying them appropriately. Introducing conflict points and attacks between coalitions based on (...) argumentative (dis)similarities to model the interaction between communities leads to considering a meta-argumentation framework where the set of coalitions plays the role of the set of arguments and where the attack relation between the coalitions is assigned a particular strength which is inherited from the arguments belonging to the coalition. Various semantics are introduced to consider attacks’ strength to particularize the effect of the new perspective. Finally, we analyze a case study where all the elements of the formal construction of the formalism are exercised. (shrink)

Everyday reasoning requires more evidence than raw data alone can provide. We explore the idea that people can go beyond this data by reasoning about how the data was sampled. This idea is investigated through an examination of premise non-monotonicity, in which adding premises to a category-based argument weakens rather than strengthens it. Relevance theories explain this phenomenon in terms of people's sensitivity to the relationships among premise items. We show that a Bayesian model of category-based induction taking premise (...) sampling assumptions and category similarity into account complements such theories and yields two important predictions: First, that sensitivity to premise relationships can be violated by inducing a weak sampling assumption; and second, that premise monotonicity should be restored as a result. We test these predictions with an experiment that manipulates people's assumptions in this regard, showing that people draw qualitatively different conclusions in each case. (shrink)

Alongside science and law, argumentation is also of central importance in everyday life. But what characterizes a good argument? This question has occupied philosophers and psychologists for centuries. The theory of Bayesian argumentation is particularly suitable for clarifying it, because it allows us to take into account in a natural way the role of uncertainty, which is central to much argumentation. Moreover, it offers the possibility of measuring the strength of an argument in probabilistic terms. One way (...) to do this, implicit in much work, is to identify the strength of an argument with the degree to which the premises of the argument confirm the conclusion. We criticize this prima facie plausible proposal and suggest instead that the strength of an argument has something to do with how much the premises and the conclusion of the argument cohere with each other. This leads to a new probabilistic measure whose properties we examine in more detail. (shrink)

Argumentation has been an important topic in knowledge representation, reasoning and multi-agent systems during the last twenty years. In this paper, we propose a new abstract framework where arguments are associated with a strength, namely a quantitative information which is used to determine whether an attack between arguments succeeds or not. Our Strength-based Argumentation Framework (StrAF) combines ideas of Preference-based and Weighted Argumentation Frameworks in an original way, which permits to define acceptability semantics sensitive to the existence of (...) accruals between arguments. The question of accruals arises in situations where several arguments defending the same position (but from different points of view) against another argument are unable to individually defeat this argument, but could do it collectively if they combine their strengths. We investigate some of the theoretical and computational properties of our new framework and semantics, and present a reasoning algorithm that is based on a translation of the problem into pseudo-boolean constraint satisfaction. This paper proposes an intuitive framework which allows strength compensations in an argumentation context where attacks may not succeed, completed by an approach which detects accruals throughout the reasoning process without requiring the elicitation of all compensatory combinations of arguments as an input. (shrink)

Argumentation is pervasive in everyday life. Understanding what makes a strong argument is therefore of both theoretical and practical interest. One factor that seems intuitively important to the strength of an argument is the reliability of the source providing it. Whilst traditional approaches to argument evaluation are silent on this issue, the Bayesian approach to argumentation (Hahn & Oaksford, 2007) is able to capture important aspects of source reliability. In particular, the Bayesian approach predicts that (...) class='Hi'>argument content and source reliability should interact to determine argument strength. In this paper, we outline the approach and then demonstrate the importance of source reliability in two empirical studies. These experiments show the multiplicative relationship between the content and the source of the argument predicted by the Bayesian framework. (shrink)

In one of his papers, Moti Mizrahi argues that arguments from an expert opinion are weak arguments. His thesis may seem controversial due to the consensus on this topic in the field of informal logic. I argue that its controversy is framework-dependent, and if translated into a different framework, it appears to be a correct, however trivial, claim. I will use a framework based on Douglas Walton’s argumentation scheme theory and his conception of examination dialogue to demonstrate that it is (...) so. It appears that Mizrahi’s idiosyncratic framework provides an excessively restrictive conception of an argument from expert opinion than Walton’s scheme does. There is no quarrel between both frameworks, as they yield analogous, almost identical, outcomes of argument evaluation. The actual and crucial disagreement is on the topic of argument classification. Mizrahi’s conception of arguments from an expert opinion imposes exact conditions that such argument must fulfil: an expert’s opinion o truth-value must be unknown; o must be unsupported by any evidence; an expert’s peers neither accept o nor reject it. These exclude, by definition, every possible strong, in Walton’s terms, variant of such an argument. Therefore, if rephrased with the notions of the examination dialogue framework, Mizrahi’s thesis sounds as follows: weak arguments from expert opinion are weak arguments. (shrink)

Both the traditional Aristotelian and modern symbolic approaches to logic have seen logic in terms of discrete symbol processing. Yet there are several kinds of argument whose validity depends on some topological notion of continuous variation, which is not well captured by discrete symbols. Examples include extrapolation and slippery slope arguments, sorites, fuzzy logic, and those involving closeness of possible worlds. It is argued that the natural first attempts to analyze these notions and explain their relation to reasoning fail, (...) so that ignorance of their nature is profound. (shrink)

Two main types of philosophical arguments have been given in support of the claim that the citizens of affluent societies have stringent moral duties to aid the global poor: “positive duty” arguments based on the notion of beneficence and “negative duty” arguments based on noninterference. Peter Singer’s positive duty argument (Singer 1972) and Thomas Pogge’s negative duty argument (Pogge 2002) are among the most prominent examples. Philosophers have made speculative claims about the relative effectiveness of these arguments in (...) promoting attitudes and behaviors that could lead to the alleviation of poverty. In this article we present the results of two empirical studies that evaluate these claims, and suggest that both arguments have a modest effect on people’s attitudes and behaviors regarding global poverty. In a replication of the second study, the negative duty argument, in particular, had a statistically significant effect on donations. We discuss the theoretical and practical significance of these results and suggest directions for further research on the role that philosophical arguments can play in engendering concern and action on pressing moral problems. (shrink)

Three studies of human nonmonotonic reasoning are described. The results show that people find such reasoning quite difficult, although being given problems with known subclass-superclass relationships is helpful. The results also show that recognizing differences in the logical strengths of arguments is important for the nonmonotonic problems studied. For some of these problems, specificity – which is traditionally considered paramount in drawing appropriate conclusions – was irrelevant and so should have lead to a “can’t tell” response; however, people could give (...) rational conclusions based on differences in the logical consequences of arguments. The same strategy also works for problems where specificity is relevant, suggesting that in fact specificity is not paramount. Finally, results showed that subjects’ success at responding appropriately to nonmonotonic problems involving conflict relies heavily on the ability to appreciate differences in the logical strength of simple, non-conflicting, statements. (shrink)

In this paper, I present the fundamental ideas of a new theory of justification strength. This theory is based on the epistemological approach to argumentation. Even the thesis of a valid justification can be false for various reasons. The theory outlined here identifies such possible errors. Justification strength is equated with the degree to which such possible errors are excluded. The natural expression of this kind of justification strength is the (rational) degree of certainty of the belief (...) in the thesis. (shrink)

The strength of emotions in moral judgment and decision-making under risk The focus of this paper is the role of emotions in judgments and choices associated with moral issues. Study 1 shows that depending on the strength of emotions when making a moral decision, people become sensitive to the severity and the probability of harm that their decisions can bring to others. A possible interpretation is that depending on the strength of emotions, people in their moral judgments (...) choose to be either utilitarian or deontologist. In Study 2, following the priority heuristic model, we found that in situations in which the violation of moral norms does not evoke strong negative emotions, people are sensitive to quantitative risk parameters, and the decision-making process requires a relatively longer time. In moral situations in which a violation of the moral norm evokes strong emotions, decision-making is based on arguments other than quantitative risk parameters, and the process takes a shorter time. (shrink)

In studying how lay people evaluate arguments, psychologists have typically focused on logical form and content. This emphasis has masked an important yet underappreciated aspect of everyday argument evaluation: social cues to argument strength. Here we focus on the ways in which observers evaluate arguments by the reaction they evoke in an audience. This type of evaluation is likely to occur either when people are not privy to the content of the arguments or when they are not (...) expert enough to appropriately evaluate it. Four experiments explore cues that participants might take into account in evaluating arguments from the reaction of the audience. They demonstrate that participants can use audience motivation, expertise, and size as clues to argument quality. By contrast we find no evidence that participants take audience diversity into account. (shrink)

Argumentation has been an important topic in knowledge representation, reasoning and multi-agent systems during the last twenty years. In this paper, we propose a new abstract framework where arguments are associated with a strength, namely a quantitative information which is used to determine whether an attack between arguments succeeds or not. Our Strength-based Argumentation Framework combines ideas of Preference-based and Weighted Argumentation Frameworks in an original way, which permits to define acceptability semantics sensitive to the existence of accruals (...) between arguments. The question of accruals arises in situations where several arguments defending the same position against another argument are unable to individually defeat this argument, but could do it collectively if they combine their strengths. We investigate some of the theoretical and computational properties of our new framework and semantics, and present a reasoning algorithm that is based on a translation of the problem into pseudo-boolean constraint satisfaction. This paper proposes an intuitive framework which allows strength compensations in an argumentation context where attacks may not succeed, completed by an approach which detects accruals throughout the reasoning process without requiring the elicitation of all compensatory combinations of arguments as an input. (shrink)

Some forms of argumentation are best performed through words. However, there are also some forms of argumentation that may be best presented visually. Thus, this paper examines the virtues of visual argumentation. What makes visual argumentation distinct from verbal argumentation? What aspects of visual argumentation may be considered especially beneficial?

This article has three purposes. First, it illustrates the strengths of social constructivism (SC) as a major thesis and its two interrelated corollaries: the “social dependency” thesis, the “communitarian” theory of meaning, and the “contingency” view of knowledge. Second, by underscoring these strengths, it will show how one can counter the anti-social critique of the kind Boghossian espouses, highlighting some genuine disagreements that cannot be resolved by appealing to the assumptions and resources that are at the heart of the matter (...) in the first place. To this end, the following points will be discussed: (1) Boghossian misses the mark primarily by focusing his main critique not on “social dependency” but on a conceptually different doctrine, namely “relativism” (defined as the “social relativity” thesis); (2) he criticizes SC by presupposing the very “non-social” view of meaning that SC was originally proposed to attack; and (3) the logic of SC “debunks” the very epistemic system on which Boghossian relies by claiming that it is as dependent on “(historical) contingencies” as any other. Finally, some responses are offered to “rationalist” concerns, which are mainly concerned with the application of SC’s logic to its own arguments. (shrink)

Rousseau insisted that his First Discourse, the Discourse on the Sciences and Arts, was chronically misread. This essay suggests that readers have tended to interpret the Discourse too narrowly. While Rousseau did link popular enlightenment with the corruption of virtue, he defined virtue as the combination of two qualities that are both separable from moral integrity and good citizenship: strength and vigor of soul. Clarifying the definition of virtue in the Discourse helps clarify Rousseau’s philosophical “system that is true (...) but distressing.” It also adds to the plausibility of Rousseau’s argument. (shrink)

In this chapter I review empirical studies directly testing the hypotheses of my 1973 paper "The Strength of Weak Ties" (hereafter "SWT") and work that elaborates those hypotheses theoretically or uses them to suggest new empirical research not discussed in my original formulation. Along the way, I will reconsider various aspects of the theoretical argument, attempt to plug some holes, and broaden its base.

This paper is about the putative theoretical virtue of strength, as it might be used in abductive arguments to the correct logic in the epistemology of logic. It argues for three theses. The first is that the well-defined property of logical strength is neither a virtue nor a vice, so that logically weaker theories are not—all other things being equal—worse or better theories than logically stronger ones. The second thesis is that logical strength does not entail the (...) looser characteristic of scientific strength, and the third is that many modern logics are on a par—or can be made to be on a par—with respect to scientific strength. (shrink)

In this paper, we report results from experiments in which people read conversational arguments and then judge the convincingness of each claim and the individual speakers' burden of proof. The results showed an "anti-primacy" effect: People judge the speaker who makes the first claim as having greater burden of proof. This effect persists even when each speaker's claims are rated equally convincing. We also find that people rate claims less convincing when they appear in the first part of an (...) class='Hi'>argument than when they appear in isolation. (shrink)

Saunders Mac Lane has drawn attention many times, particularly in his book Mathematics: Form and Function, to the system of set theory of which the axioms are Extensionality, Null Set, Pairing, Union, Infinity, Power Set, Restricted Separation, Foundation, and Choice, to which system, afforced by the principle, , of Transitive Containment, we shall refer as . His system is naturally related to systems derived from topos-theoretic notions concerning the category of sets, and is, as Mac Lane emphasises, one that is (...) adequate for much of mathematics. In this paper we show that the consistency strength of Mac Lane's system is not increased by adding the axioms of Kripke–Platek set theory and even the Axiom of Constructibility to Mac Lane's axioms; our method requires a close study of Axiom H, which was proposed by Mitchell; we digress to apply these methods to subsystems of Zermelo set theory , and obtain an apparently new proof that is not finitely axiomatisable; we study Friedman's strengthening of , and the Forster–Kaye subsystem of , and use forcing over ill-founded models and forcing to establish independence results concerning and ; we show, again using ill-founded models, that proves the consistency of ; turning to systems that are type-theoretic in spirit or in fact, we show by arguments of Coret and Boffa that proves a weak form of Stratified Collection, and that is a conservative extension of for stratified sentences, from which we deduce that proves a strong stratified version of ; we analyse the known equiconsistency of with the simple theory of types and give Lake's proof that an instance of Mathematical Induction is unprovable in Mac Lane's system; we study a simple set theoretic assertion—namely that there exists an infinite set of infinite sets, no two of which have the same cardinal—and use it to establish the failure of the full schema of Stratified Collection in ; and we determine the point of failure of various other schemata in . The paper closes with some philosophical remarks. (shrink)

Recent approaches to studying argumentation in institutions have pointed out the role of institutional rules in constraining argumentation that takes place in institutional contexts. However, few studies explain how these rules concretely affect actual argumentation. In particular, little work has been done as to the consequences of interactional asymmetry which often exists between participants in institutional contexts. While previous studies have suggested that this asymmetry exists as an aberration in the deliberative process, this paper argues that asymmetry is built into (...) day-to-day institutional practices as a means of achieving institutional agendas. This article draws upon findings from workplace and discourse studies to explicate particular dimensions of asymmetry that commonly occur within institutional settings, and establishes a methodological framework to account for how this asymmetry can be operationalized for arguments that favor institutional interests regardless of the underlying strength of the arguments being made. Drawing on a controversial case of institutional argumentation during a hearing of the US House Committee on Un-American Activities in the mid-1950s, this article demonstrates how in using these advantages, HUAC is able to overcome legitimate witness counterarguments to its claims and achieve its institutional goals for the hearing. Though the testimony is admittedly 60-years old, HUAC is a useful case study: the asymmetry in the exchange is clear and we have a historical record to verify the factual accuracy of the claims being made. Additionally, we can see how the subsequent legal reforms that reduced conditions of asymmetry for witnesses were responsible for HUAC’s eventual demise as an institutional force. Though this paper analyzes one particular interaction, these findings are applicable to analysis of argumentation in many institutional settings. (shrink)

This paper attempts to address the question what logical strength theories of truth have by considering such questions as: If you take a theory T and add a theory of truth to it, how strong is the resulting theory, as compared to T? It turns out that, in a wide range of cases, we can get some nice answers to this question, but only if we work in a framework that is somewhat different from those usually employed in discussions (...) of axiomatic theories of truth. These results are then used to address a range of philosophical questions connected with truth, such as what Tarski meant by "essential richness" and the so-called conservativeness argument against deflationism. -/- This draft dates from about 2009, with some significant updates having been made around 2011. Around then, however, I decided that the paper was becoming unmanageable and that I was trying to do too many things in it. I have therefore exploded the paper into several pieces, which will be published separately. These include "Disquotationalism and the Compositional Principles", "The Logical Strength of Compositional Principles", "Consistency and the Theory of Truth", and "What Is Essential Richness?" You should probably read those instead, since this draft remains a bit of a mess. Terminology and notation are inconsistent, and some of the proofs aren't quite right. So, caveat lector. I make it public only because it has been cited in a few places now. (shrink)

This commentary agrees with Mercier and Sperber's (M&S's) thesis on the argumentative function of reasoning but suggests that an account of argument strength is required. A Bayesian account of argument strength (Hahn & Oaksford 2007) shows how the deployment of deductive fallacies, weak inductive arguments, and judgment fallacies such as base-rate neglect, can all be rationally defended in the right argumentative context.

George Harris argues that human frailty, indeed vulnerability to utter and complete psychological breakdown in the form “a loss of the will to live, deep clinical depression, insanity, hysteria, debilitating shame, [and] pervasive self-deception,” is a source of our special dignity as persons. This type of fragility is a sign of a higher quality of character, he argues; a quality that is lacking in anyone who has the inner strength to survive the worst of life’s hardships without suffering “a (...) form of personal disintegration that renders the person dysfunctional as an agent”. This is a striking and extreme thesis. It is not the less controversial and more plausible thesis that virtue involves a capacity to experience, in the right way and at the right time, a broad range of feelings and emotions. An investigation of the psychological traits and vulnerabilities that are connected to virtue is a very interesting topic worthy of extensive discussion. Although this book contributes to this worthwhile discussion, the argument for the book’s controversial thesis is not convincing. (shrink)

_ Source: _Volume 14, Issue 1, pp 73 - 87 According to action-relative accounts of harming, an action harms someone only if it makes her worse off in some respect than she would have been, had the action not been performed. Action-relative accounts can be contrasted with effect-relative accounts, which hold that an action may harm an individual in virtue of its effects on that individual, regardless of whether the individual would have been better off in the absence of the (...) action. In this paper, I argue that our judgments about the strength of the reason against harming lend support to effect-relative accounts over action-relative accounts. I first criticize Fiona Woollard’s argument for the claim that an effect-relative account of harming could ground only a weak reason against harming. I then argue for a set of three principles that can be conjoined with an effect-relative account to explain the strength of the reason against harming. (shrink)

The Values in Action (VIA) classification of character strengths and virtues has been recently proposed by two leading positive psychologists, Christopher Peterson and Martin Seligman as “the social science equivalent of virtue ethics.” The very possibility of developing this kind of an “equivalent,” however, is very doubtful in the light of the cogent criticism that has been leveled at modern moral theory by Alasdair MacIntyre as well as the well argued accusations that positive psychology, despite its official normative neutrality, is (...) pervaded by specifically Western individualism and instrumentalism. In order to evaluate whether the VIA project can be considered as substantially rooted in virtue ethical tradition, the classification was assessed against two fundamental features of the classical version of the latter: (1) the substantial interconnectedness of individual virtues, as expressed by the thesis of the unity of virtue, and (2) the constitutive character of the relationship between virtue and happiness. It turned out, in result, that the two above features are not only absent from but also contradicted by the VIA framework with the latter's: (1′) construal of individual virtues and character strengths as independent variables and (2′) official endorsement of the fact/value distinction. As soon as the arguments for the superiority of the classical virtue ethical perspective are provided, the potential responses available to the VIA's proponents are discussed. (shrink)

Common sense arguments are practically always about incomplete and uncertain information. We distinguish two aspects or kinds of uncertainty. The one is defined as a persons’ uncertainty about the truth of a sentence. The other uncertainty is defined as a persons’ uncertainty of his assessment of the truth of a sentence. In everyday life argumentation we are often faced with both kinds of uncertainty which should be distinguished to avoid misunderstandings among discussants. The paper presents a probabilistic account of both (...) kinds of uncertainty in the framework of coherence. Furthermore, intuitions about the evaluation of the strength of arguments are explored. Both reasoning about uncertainty and the development of a theory of argument strength are central for a realistic theory of rational argumentation. (shrink)

Four important arguments for probabilism—the Dutch Book, representation theorem, calibration, and gradational accuracy arguments—have a strikingly similar structure. Each begins with a mathematical theorem, a conditional with an existentially quantified consequent, of the general form: if your credences are not probabilities, then there is a way in which your rationality is impugned.Each argument concludes that rationality requires your credences to be probabilities.I contend that each argument is invalid as formulated. In each case there is a mirror-image theorem and (...) a corresponding argument of exactly equal strength that concludes that rationality requires your credences not to be probabilities. Some further consideration is needed to break this symmetry in favour of probabilism. I discuss the extent to which the original arguments can be buttressed.1. Introduction2. The Dutch Book Argument2.1. Saving the Dutch Book argument2.2. ‘The Dutch Book argument merely dramatizes an inconsistency in the attitudes of an agent whose credences violate probability theory’3. Representation Theorem-based Arguments4. The Calibration Argument5. The Gradational Accuracy Argument6. Conclusion. (shrink)

Most of the contemporary literature regarding teleology or design in nature assumes that we human beings make some sort of tacit inference when we form "design beliefs" person is causally relevant to the occurrence of some event). It is often held that this inference occurs so quickly that we are unaware of the inferential process. Attempts to reconstruct this inference have met with varying degrees of success, but none of them seem to match the strength with which ordinary design (...) beliefs are held. This dissertation therefore offers a challenge to this "inferential model" of design belief formation by arguing that in many ordinary cases we do not infer to design beliefs at all. Rather, human design beliefs often form spontaneously and properly whenever certain conditions are met, and receive some measure of positive epistemic status just in virtue of their proper and spontaneous formation. This alternative model is called a "Reidian" model because it is analogous to Thomas Reid's account of sense perception. The Reidian model offers the dialectical advantage of shifting the burden of proof from the one arguing for design to the one who claims to have a suitable "defeater" belief. It also better matches our introspective judgments about design beliefs and resolves some puzzling problems that have been noted in recent literature on design inferences. ;The Reidian model can also generate some reasonably persuasive design arguments from the deliverances of the natural sciences , but it does not sanction the inclusion of design hypotheses within the content of the natural sciences. It is also argued that none of the "defeater" propositions one might consider carries enough epistemic "weight" to defeat design beliefs that form according to the model. The resulting Reidian design arguments also have the advantage that they do not require the rejection of the Darwinian paradigm. However, it is also noted that the Reidian model presents several occasions for dialectical impasse between disputants about design in nature. (shrink)