Since the 1980s consensus opinion is that the mind is like a collection of specialised modules each tasked for a specific purpose. The author seeks to elucidate and account for this theory and explain what it means to be human in this context.

A new pragmatic approach, based on the latest developments in argumentation theory, analyzing appeal to expert opinion as a form of argument. Reliance on authority has always been a common recourse in argumentation, perhaps never more so than today in our highly technological society when knowledge has become so specialized—as manifested, for instance, in the frequent appearance of "expert witnesses" in courtrooms. When is an appeal to the opinion of an expert a reasonable type of argument to make, and when (...) does it become a fallacy? This book provides a method for the evaluation of these appeals in everyday argumentation. Specialized domains of knowledge such as science, medicine, law, and government policy have gradually taken over as the basis on which many of our rational decisions are made daily. Consequently, appeal to expert opinion in these areas has become a powerful type of argument. Challenging an argument based on expert scientific opinion, for example, has become as difficult as it once was to question religious authority. Walton stresses that even in cases where expert opinion is divided, the effect of it can still be so powerful that it overwhelms an individual's ability to make a decision based on personal deliberation of what is right or wrong in a given situation. The book identifies the requirements that make an appeal to expert opinion a reasonable or unreasonable argument. Walton's new pragmatic approach analyzes that appeal as a distinctive form of argument, with an accompanying set of appropriate critical questions matching the form. Throughout the book, a historical survey of the key developments in the evolution of the argument from authority, dating from the time of the ancients, is given, and new light is shed on current problems of "junk science" and battles between experts in legal argumentation. (shrink)

This paper examines social network size in contemporary Western society based on the exchange of Christmas cards. Maximum network size averaged 153.5 individuals, with a mean network size of 124.9 for those individuals explicitly contacted; these values are remarkably close to the group size of 150 predicted for humans on the basis of the size of their neocortex. Age, household type, and the relationship to the individual influence network structure, although the proportion of kin remained relatively constant at around 21%. (...) Frequency of contact between network members was primarily determined by two classes of variable: passive factors (distance, work colleague, overseas) and active factors (emotional closeness, genetic relatedness). Controlling for the influence of passive factors on contact rates allowed the hierarchical structure of human social groups to be delimited. These findings suggest that there may be cognitive constraints on network size. (shrink)

Th is chapter outlines the theory (fi rst explicitly defended by Pinker and Bloom 1990), that the human language faculty is a complex biological adaptation that evolved by natural selection for communication in a knowledgeusing, socially interdependent lifestyle. Th..

Walton gives a clear method for analyzing and evaluating cases of ad hominem arguments found in everyday argumentation.

Robert Merton observed that better-known scientists tend to get more credit than less well-known scientists for the same achievements; he called this the Matthew effect. Scientists themselves, even those eminent researchers who enjoy its benefits, regard the effect as a pathology: it results, they believe, in a misallocation of credit. If so, why do scientists continue to bestow credit in the manner described by the effect? This paper advocates an explanation of the effect on which it turns out to allocate (...) credit fairly after all, while at the same time making sense of scientists' opinions to the contrary. (shrink)

This paper provides a typology of appeals to authority, identifying three distinct types: that which is based on a command; that which is based on expertise; and that which is based on dignity. Each type is distinguished with respect to the reaction that a failure to follow it ordinarily evokes. The rhetorical roots of Locke's ad verecundiam are traced to the rhetorical practices of ancient Rome.

1. When we attribute beliefs, desires, and other states of common sense psychology to a person, or for that matter to an animal or an artifact, we are assuming or presupposing that the person or object can be treated as an intentional system. 2. An intentional system is one which is rational through and through; its beliefs are those it ought to have, given its perceptual capacities, its epistemic needs, and its biography…. Its desires are those it ought to have, (...) given its biological needs and the most practicable means of satisfying them…. And its behavior will consist of those acts that it would be rational for an agent with those beliefs and desires to perform. [beliefs + desires  action] 3. If rationality is absent, we cannot coherently ascribe beliefs at all. 4. Therefore, no experiment could demonstrate that people systematically invoke invalid or irrational inferential strategies. (shrink)