In a paper and a reply to critics published in _Informal Logic_, I argue that arguments from expert opinion are weak arguments. To appeal to expert opinion is to take an expert’s judgment that _p_ is the case as evidence for _p_. Such appeals to expert opinion are weak, I argue, because the fact that an expert judges that _p_ does not make it significantly more likely that _p_ is true or probable, as evidence from empirical studies on expert performance (...) suggests. Unlike other critics of this argument, who take issue with the empirical evidence on expert performance, David Botting says that he wants to take issue with the premise that reliability is a necessary condition for the strength of appeals to expert opinion. I respond to Botting’s objections and argue that they miss their intended target. I also argue that his attempt to show that arguments from expert opinion are strong is unsuccessful. (shrink)

In this paper I will argue that there is an inductive and a non-inductive argument from position to know, and will characterise the latter as an argument from authority because of providing content-independent reasons. I will also argue that both types of argument should be doubt-preserving: testimony cannot justify a stronger cognitive attitude in the arguer than the expert herself expresses when she testifies. Failure to appreciate this point undercuts Mizrahi’s claim that arguments from expert opinion are weak.

Accounts of arguments from expert opinion take it for granted that expert judgments count as (defeasible) evidence for propositions, and so an argument that proceeds from premises about what an expert judges to a conclusion that the expert is probably right is a strong argument. In Mizrahi (2013), I consider a potential justification for this assumption, namely, that expert judgments are significantly more likely to be true than novice judgments, and find it wanting because of empirical evidence suggesting that expert (...) judgments under uncertainty are not significantly more likely to be true than novice judgments or even chance. In this paper, I consider another potential justification for this assumption, namely, that expert judgments are not influenced by the cognitive biases novice judgments are influenced by, and find it wanting, too, because of empirical evidence suggesting that experts are vulnerable to pretty much the same cognitive biases that novices are vulnerable to. If this is correct, then the basic assumption at the core of accounts of arguments from expert opinion, namely, that expert judgments count as (defeasible) evidence for propositions, remains unjustified. (shrink)

In this paper, I present the results of an experimental study on intuitions about moral obligation (ought) and ability (can). Many philosophers accept as an axiom the principle known as “Ought Implies Can” (OIC). If the truth of OIC is intuitive, such that it is accepted by many philosophers as an axiom, then we would expect people to judge that agents who are unable to perform an action are not morally obligated to perform that action. The results of my experimental (...) study show that participants were more inclined to judge that an agent ought to perform an action than that the agent can perform the action. Overall, participants said that an agent ought to perform an action even when they said that the agent cannot do it. I discuss the implications of these results for the debate over OIC. (shrink)

In this paper we show that an essential aspect of solving the problem of uncritical acceptance of expert opinions that is at the root of the ad verecundiam fallacy is the need to disentangle argument from expert opinion from another kind of appeal to authority. Formal and computational argumentation systems enable us to analyze the fault in which an error has occurred by virtue of a failure to meet one or more of the requirements of the argumentation scheme from argument (...) from expert opinion. We present a method for enhancing this capability by showing how arguments from expert opinion are related to, but different from, arguments from deontic authority. (shrink)

In this paper we describe the impact that Walton’s conception of argumentation schemes had on AI and Law research. We will discuss developments in argumentation in AI and Law before Walton’s schemes became known in that community, and the issues that were current in that work. We will then show how Walton’s schemes provided a means of addressing all of those issues, and so supplied a unifying perspective from which to view argumentation in AI and Law.

Le projet philosophique puise ses sources dans la volonté de proposer une explication rationnelle des phénomènes naturels et culturels qui constituent le monde dans lequel l’être humain prend place. Il a servi de trame culturelle à l’Occident et amené le déploiement d’appareils conceptuels où l’on distingue théorie et pratique. On doit toutefois reconnaître qu’une philosophie théorique peut avoir une portée pratique et l’inverse, puisque toute pratique suppose un ancrage théorique pour légitimer la connaissance et les systèmes normatifs à partir desquels (...) les explications sont avancées. Cela fait dire à certains que la distinction est désormais surannée et qu’une théorie philosophique réunifiée s’impose. Que l’on soit tenant de la tradition ou des nouvelles approches, la philosophie pratique s’impose désormais comme un passage obligé pour réfléchir les problèmes et articuler de nouvelles théories faisant écho à l’état actuel de notre monde. Le présent ouvrage revient sur la notion de philosophie pratique afin d’en faire voir les différentes acceptions et manières de la mobiliser pour réfléchir à des problèmes actuels. (shrink)

This paper outlines an integrated approach to trust and relevance with respect to arguments: in particular, it is suggested that trust in relevance has a central role in argumentation. We first distinguish two types of argumentative relevance: internal relevance, i.e. the extent to which a premise has a bearing on its purported conclusion, and external relevance, i.e. a measure of how much a whole argument is pertinent to the matter under discussion, in the broader dialogical context where it is proposed. (...) Then, we argue that judgements of internal relevance heavily rely on trust, and that such trust, although occasionally misplaced , is nonetheless based on several reasons, and thus often justified, by either epistemic or pragmatic considerations. We conclude by sketching potential methods to formally model trust in argumentative relevance, and briefly discussing the technological implications of this line of research. (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)