In this article, I present a schema for generating counterexamples to the argument form known as Hypothetical Syllogism with indicative conditionals. If my schema for generating counterexamples to HS works as I think it does, then HS is invalid for indicative conditionals.

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

In this article the standard philosophical method involving intuition-driven conceptual analysis is challenged in a new way. This orthodox approach to philosophy takes analysanda to be the specifications of the content of concepts in the form of sets of necessary and sufficient conditions. Here it is argued that there is no adequate account of what necessary and sufficient conditions are. So, the targets of applications of the standard philosophical method so understood are not sufficiently well understood for this method to (...) be dependable. (shrink)

Several authors have recently begun to apply virtue theory to argumentation. Critics of this programme have suggested that no such theory can avoid committing an ad hominem fallacy. This criticism is shown to trade unsuccessfully on an ambiguity in the definition of ad hominem. The ambiguity is resolved and a virtue-theoretic account of ad hominem reasoning is defended.

Three forms of the straw man fallacy are posed: the straw, weak, and hollow man. Additionally, there can be non-fallacious cases of any of these species of straw man arguments.

If good argument is virtuous, then fallacies are vicious. Yet fallacies cannot just be identified with vices, since vices are dispositional properties of agents whereas fallacies are types of argument. Rather, if the normativity of good argumentation is explicable in terms of virtues, we should expect the wrongness of fallacies to be explicable in terms of vices. This approach is defended through case studies of several fallacies, with particular emphasis on the ad hominem.

Fallacies of relevance, a major category of informal fallacies, include two that could be called pure fallacies of relevance-the wrong conclusion (ignoratio elenchi, wrong conclusion, missing the point) fallacy and the red herring digression, diversion) fallacy. The problem is how to classify examples of these fallacies so that they clearly fall into the one category or the other, on some rational system of classification. In this paper, the argument diagramming software system, Araucaria. is used to analyze the argumentation in some (...) selected textbook examples of pure fallacies of relevance. A system of classification of these fallacies is proposed, and criteria for determining whether an example should be classified as wrong conclusion or red herring are formulated. A key difference cited is that in a case where the red herring fallacy has been committed, even if the argument may go to a wrong conclusion, there is evidence of the use ofa deceptive tactic of diversion. Textual evidence must indicate that the arguer deliberately interjects a distracting controversy to lead the respondent away from the real issue to be disputed. (shrink)

In this paper, I argue that arguments from expert opinion, i.e., inferences from “Expert E says that p” to “p,” where the truth value of p is unknown, are weak arguments. A weak argument is an argument in which the premises, even if true, provide weak support—or no support at all—for the conclusion. Such arguments from expert opinion are weak arguments unless the fact that an expert says that p makes p significantly more likely to be true. However, research on (...) expertise shows that expert opinions are only slightly more accurate than chance and much less accurate than decision procedures. If this is correct, then it follows that arguments from expert opinion are weak arguments. (shrink)

Analogical reasoning projects a property taken to hold of something or things (the source) to something else (the target) on the basis of just those similarities premised in the analogy. Standard similarity-based accounts of analogical reasoning face the question: Under what conditions does a collection of similarities sufficiently warrant analogical projection? One answer is: When a thing’s having the premised similarities somehow determines its having the projected property. Standardly, this answer has been interpreted as claiming that a formally defined determination (...) relation exists between the variables of which the determining properties are values and the variable of which the determined property is a value. This paper supplies another answer: Analogical projection is warranted when an item’s having the projected property is grounded in its having the premised similarities. Drawing on the metaphysics of grounding, we propose a model of grounded analogy on which analogical reasoning is valid under metaphysical necessity. Our model thus provides one answer to John Stuart Mill’s question of how analogical reasoning based on limited information about a single source case can provide an indefeasible justification for analogical projection. Once a relation of total grounding is ascertained to hold between some similarities and the projected property, no other properties bear on the projectability of the projected property from the source to the target. (shrink)