Christopher Tindale
1. Strong and weak argument[1],[2]
Arguments come in a range of types and employing a diversity of devices, from those that press a historical case using causal reasoning to those that recommend an economic course of action by appealing to an authority in the field. They will be characterized by a particular structure where one or more statements (premises) are given in support of a conclusion, and a range of intentions: to persuade an audience, to resolve a dispute, to achieve agreement in a negotiation, to recommend an action, or to complete an inquiry. Because of these different intentions, arguments arise in different contexts that are part of the argumentative situation. Arguments also come in a range of strengths, from those that conform to the principles of good reasoning, to those that commit some of the more abysmal errors that occur with some regularity. In between, are degrees of strength and weakness. In fact, many arguments of a more extended nature will admit of merits and demerits that can make our judgment about the overall quality of the reasoning quite difficult. A fallacy is a particular kind of egregious error, one that seriously undermines the power of reason in an argument by diverting it or screening it in some way. But a more precise definition is difficult to give and depends on a range of considerations.
One famous definition of ‘fallacy’ that C.L. Hamblin[3] derives from the Aristotelian tradition states: “A fallacious argument, as almost every account from Aristotle onwards tells you, is one that seems to be valid but is not so.” This raises three central questions: Are fallacies all and only arguments, because Hamblin’s definition is, strictly speaking, a definition of ‘fallacious argument’? Are fallacies all a matter of validity, which seems to restrict attention to the relations between the parts of an argument? And are fallacies detected through their psychological effect, because if they seem valid they must seem so to someone?
To consider these questions and the kinds of problematic reasoning that may be elevated (or demoted) to the status of “fallacy” we will explore the following two cases:
Case A: This is from a letter sent to Scientific American (January 2, 2002) and it concerns the so-called Lomborg affair, a controversy that erupted in major scientific publications after Bjørn Lomborg published his book, The Skeptical Environmentalist, in which he challenged many “orthodoxies” of the environmental movement.
In the 1970s there was a lot of excitement over two books: one theorized that our planet had been visited by friendly aliens who had helped our ancestors with all kinds of “impossible” achievements, including the building of the pyramids; another proposed paranormal explanations for the Bermuda Triangle, complete with “irrefutable” evidence. I can’t remember the titles of these books or the authors’ names, but I do remember watching one of them being interviewed on television. Althoug