This chapter introduces and discusses the concepts of necessary and sufficient conditions.

There is no concept more central to logic and critical thinking than the concept of an argument. I here address the definition of ‘argument’ in the logical sense of the term and defend the claim that many current proposals, once they are interpreted in a way that makes them sufficiently precise, are extensionally inadequate. Definitions found in some contemporary, prominent critical thinking textbooks will serve as a springboard. I claim that each may be interpreted in an absolutist way or a (...) relativistic way, yet all turn out to be objectionable no matter which route is taken. I finish with a proposal on which the definition of ‘argument’ is an absolutist one, yet one that avoids the problems discussed for the earlier proposals. (shrink)

In this paper, I argue that, other things being equal, simpler arguments are better. In other words, I argue that, other things being equal, it is rational to prefer simpler arguments over less simple ones. I sketch three arguments in support of this claim: an argument from mathematical proofs, an argument from scientific theories, and an argument from the conjunction rule.

This paper applies speech-act theory to craft a new response to Pyrrhonian skepticism and diagnose its appeal. Carefully distinguishing between different levels of language-use and noting their interrelations can help us identify a subtle mistake in a key Pyrrhonian argument.

In this paper, I propose that applying the methods of data science to “the problem of whether mathematical explanations occur within mathematics itself” (Mancosu 2018) might be a fruitful way to shed new light on the problem. By carefully selecting indicator words for explanation and justification, and then systematically searching for these indicators in databases of scholarly works in mathematics, we can get an idea of how mathematicians use these terms in mathematical practice and with what frequency. The results of (...) this empirical study suggest that mathematical explanations do occur in research articles published in mathematics journals, as indicated by the occurrence of explanation indicators. When compared with the use of justification indicators, however, the data suggest that justifications occur much more frequently than explanations in scholarly mathematical practice. The results also suggest that justificatory proofs occur much more frequently than explanatory proofs, thus suggesting that proof may be playing a larger justificatory role than an explanatory role in scholarly mathematical practice. (shrink)

Some arguments are good; others are not. How can we tell the difference? This article advances three proposals as a partial answer to this question. The proposals are keyed to arguments conditioned by different degrees of uncertainty: mild, where the argument’s premises are hedged with point-valued probabilities; moderate, where the premises are hedged with interval probabilities; and severe, where the premises are hedged with non-numeric plausibilities such as ‘very likely’ or ‘unconfirmed’. For mild uncertainty, the article proposes to apply a (...) principle referred to as ‘Jeffrey’s rule’, for the principle is a generalization of Jeffrey conditionalization. For moderate uncertainty, the proposal is to extend Jeffrey’s rule for use with probability intervals. For severe uncertainty, the article proposes that even when lack of probabilistic information prevents the application of Jeffrey’s rule, the rule can be adapted to these conditions with the aid of a suitable plausibility measure. Together, the three proposals introduce an approach to argument evaluation that complements established frameworks for evaluating arguments: deductive soundness, informal logic, argumentation schemes, pragma-dialectics, and Bayesian inference. Nevertheless, this approach can be looked at as a generalization of the truth and validity conditions of the classical criterion for sound argumentation. (shrink)

In this essay I show how to reconcile epistemic invariantism with the knowledge account of assertion. My basic proposal is that we can comfortably combine invariantism with the knowledge account of assertion by endorsing contextualism about speech acts. My demonstration takes place against the backdrop of recent contextualist attempts to usurp the knowledge account of assertion, most notably Keith DeRose's influential argument that the knowledge account of assertion spells doom for invariantism and enables contextualism's ascendancy.

“Meta-argument allegations” consist of protestations that an interlocutor’s speech is wrongfully offensive or will trigger undesirable social consequences. Such protestations are meta-argument in the sense that they do not interrogate the soundness of an opponent’s argumentation, but instead focus on external features of that argument. They are allegations because they imply moral wrongdoing. There is a legitimate place for meta-argument allegations, and the moral and epistemic goods that can come from them will be front of mind for those levelling such (...) allegations. But I argue there is a dark side to such allegations, and their epistemic and moral costs must be seriously weighed. Meta-argument allegations have a concerning capacity to derail discussions about important topics, stymieing argumentational interactions and the goods they provide. Such allegations can license efforts to silence, punish and deter—even as they provoke the original speaker to retaliate in kind. Used liberally, such allegations can escalate conflicts, block open-mindedness, and discourage constructive dialogues. In response, I defend “argumentational tolerance”—a principled wariness in employing meta-argument allegations—as a virtue of ethical argument. (shrink)

Research in the field of Empirical Ethics (EE) uses a broad variety of empirical methodologies, such as surveys, interviews and observation, developed in disciplines such as sociology, anthropology, and psychology. Whereas these empirical disciplines see themselves as purely descriptive, EE also aims at normative reflection. Currently there is literature about the quality of empirical research in ethics, but little or no reflection on specific methodological aspects that must be considered when conducting interdisciplinary empirical ethics. Furthermore, poor methodology in an EE (...) study results in misleading ethical analyses, evaluations or recommendations. This not only deprives the study of scientific and social value, but also risks ethical misjudgement. (shrink)

Argumentation logicians have recognized a specter of relativism to haunt their philosophy of argument. However, their attempts to dispel pernicious relativism by invoking notions of a universal audience or a community of model interlocutors have not been entirely successful. In fact, their various discussions of a universal audience invoke the context-eschewing formalism of Kant’s categorical imperative. Moreover, they embrace the Kantian method for resolving the antinomies that continually vacillates between opposing extremes – here between a transcendent universal audience and a (...) context-embedded particular audience. This tack ironically restores the very external mediation they thought to obviate in their aim to ‘dethrone’ the absolutism and totalitarianism of formal logic with a democratic turn to audience adherence, the acceptability of premises and inferential links, and a contextual, or participant-relative, notion of cogency. (shrink)

I advance a pragmatic account of begging the question according to which a use of an argument begs the question just in case it is used as a statement of inference and it fails to state an inference the arguer or an addressee can perform given what they explicitly believe. Accordingly, what begs questions are uses of arguments as statements of inference, and the root cause of begging the question is an argument’s failure to state an inference performable by the (...) reasoners the arguer targets. In these ways, my account is distinguished from other pragmatic accounts. By taking the defect of a question-begging use of an argument to be its failure to state its purported inference, my account highlights in a unique way why question-begging is not an epistemic defect, and why it is not a fallacy, understood as a mistake in reasoning. These points have been made elsewhere, but I believe that their plausibility is enhanced by considering begging the question as nullifying the role of an argument as a statement of inference. Since question-begging uses of arguments fail to state their purported inferences, using an argument in a question-begging-way is not a ratiocinative mistake. This undermines accounts of begging the question that adopt an epistemic approach. (shrink)

Even with the lack of consensus on the nature of an argument, the thesis that explanations and arguments are distinct is near orthodoxy in well-known critical thinking texts and in the more advanced argumentation literature. In this paper, I reconstruct two rationales for distinguishing arguments from explanations. According to one, arguments and explanations are essentially different things because they have different structures. According to the other, while some explanations and arguments may have the same structure, they are different things because (...) explanations are used for different purposes than arguments. I argue that both rationales fail to motivate a distinction between arguments and explanations. Since these are the only rationales for distinguishing arguments from explanations that I am prepared to take seriously, I don’t see why we should exclude explanations from being arguments. (shrink)

It can be argued that there is an ethical requirement to classify correctly what is known and what is unknown in decision situations, especially in the context of biomedicine when risks and benefits have to be assessed. This is because other methods for assessing potential harms and benefits, decision logics and/or ethical principles may apply depending on the kind or degree of uncertainty. However, it is necessary to identify and describe the various epistemic states of uncertainty relevant to such estimates (...) in the first place. Therefore, this paper aims to develop a category system of different epistemic states of uncertainty which, although not exclusively, is primarily intended to be applied to early clinical trials. It is formed on the basis—and various combinations—of three dimensions of uncertainty that represent certain parts of incomplete knowledge: outcome (type of event), probability (of outcome) and evaluation (assessment of outcome). Furthermore, it is argued that uncertainty can arise from three different sources (the structure of the object of research, the state of the evidence, or individual handling of the research and already existing knowledge). The categories developed are applied to actual examples from gene therapy and genome editing to illustrate that they can be helpful for a more precise definition of the respective uncertainties, especially in the context of risk–benefit assessment. The categories allow a differentiated perspective of decision-making situations from the point of view of incomplete knowledge in general, but particularly, for example, in early clinical research, and may thereby support a more acceptable ethical assessment of potential harms and benefits. (shrink)

This essay has two purposes. The first is to argue that our moral duties towards human embryos should be assessed in light of the Golden Rule by asking the normative question, “how would I want to be treated if I were an embryo?” Some reject the proposition “I was an embryo” on the basis that embryos should not be recognized as persons. This essay replies to five common arguments denying the personhood of human embryos: (1) that early human embryos lack (...) ontological individuation; (2) that they are members of the species Homo sapiens but not yet human persons; (3) that the argument for personhood commits the “heap argument” fallacy; (4) that since human procreation in nature is inefficient, human embryos cannot be persons; and (5) the “burning building” scenario proves that all arguments for personhood are irrational or inconsistent. The second purpose is to set forth and criticize in light of the normative judgement defended in part one the present legal situation of cryo-preserved embryos in the U.S. The essay ends by proposing legislative reforms to protect ex utero human embryos. (shrink)

I argue in a non-reductive sense for a plausible epistemic principle, which can (1) theoretically and instrumentally unify or systematize all fallacies, and (2) provide a justification for using such a principle for characterizing an erroneous argument as a fallacy. This plausible epistemic principle involves the idea of an error in the method of justification, which results in a failure to provide relevant evidence to satisfy certain standards of adequate proof. Thus, all fallacies are systematically disguised failures to provide substantive (...) proof: a failure in the attempt to persuade rationally, as opposed to emotionally or rhetorically. I argue that the epistemic idea of begging the question is essential to this idea of a fallacy as an inadequate proof. (shrink)