Reasoning: A Practical Guide for Canadian Students

Anyone tasked with the joyous labor of teaching informal logic or critical thinking should take a serious look at this text, which fulfills its promise of offering a practical guide. It begins with an anatomy of the reasoning process, then proceeds to various sources for reasoning such as the media, opinion polls, and experimental research. Part I, Claims, gets students comfortable with the notions of claim, assert, and imply, as well as with the indirect communication forms of innuendo and irony. Then a discussion of the credibility of sources paves the way for the next section, Information and the Media. In that section, the discussion on bias offers a crucial distinction between bias defined as an unfair view and bias as a position out of which a person reasons (the latter for example, "It's my bias that people are more equal than not"). Part I ends with sections on news media and offers a news media checklist of over a dozen questions that, as the authors explain, "an active, critical media comsumer will ask and try to answer" (p.57). Part II, Inferences, shows students that this process is central to reasoning, and expands the student's vocabulary and understanding of propositions, premisses, grounds and conclusions, with lively examples about pending summer jobs and compact disk players that students will like. There are two very useful tables. One, called Role Indicator Words, offers terms such as "therefore," "although," and "must," with an account of their logical relation to the whole idea which is being expressed. The other, Assertion Qualifiers, points to adverbial phrases such as "certainly," "maybe," and to parenthetical phrases such as "I suspect," "as far as I know," to alert students that a writer is ascribing a belief that he or she holds towards a proposition. The next section shows students how inferences can have the logical properties of compound propositions, entailment, equivalence, incompatability or consistency, or contradiction. Then Evaluating Inferences offers several handy ideas, such as the notion that support for an