Evaluating Logical Appeals LOGOS LOGOS Arguing through reasoning, The presentation of rational thought through language. Appeals to our ability to think LOGOS IS NOT LIKE MATH Reason and “common sense” depend on cultural assumptions, which is one reason that people can disagree even when faced with the same facts. ARGUMENT = CLAIM + GROUNDS Claim: Statement under dispute. What the author is trying to prove. Grounds: Reasons and evidence that support the claim Warranting Assumption: A (hopefully) shared belief that connects the claim to the grounds. TYPES OF CLAIMS (STASES) Existence/Fact: What is the nature of reality? Definition/Language: How should words or events be defined or interpreted? Causality: What are the causes or effects of an event? Values: What is the value of an object? Is it good or bad? Action: What should we do? What actions or policies will solve a particular problem? GROUNDS Reasons and evidence that support the claim Often signaled by words like because, therefore, and so. Grounds may also be claims and need further support or evidence. COMMON SENSE AND HARD EVIDENCE Common Sense is reasoning based on logical interpretation of hard evidence cultural assumptions habits of mind Hard evidence can be counted, measured, photographed, recorded Examples Authorities Testimony Polls Studies Statistics Hard evidence cannot be trusted automatically, needs to be scrutinized. WARRANTING ASSUMPTIONS A (hopefully) shared belief that connects the claim to the grounds. A value—often taken for granted—that underlies the argument Ask yourself, “If the reason is true, what else must be true for the claim to be true.” IMPLICIT AND EXPLICIT WARRANTS Warrants are usually implied, unstated. When you look for warrants, you are drawing inferences. Warrants are sometimes stated explicitly, especially when the author thinks the audience may not share his or her assumptions. The author may then argue for the validity of the warrant by offering additional backing. Backing is reasons or evidence used to support the warrant. TYPES OF WARRANTS: GASCAP G – Generalization A – Analogy S – Sign C – Causality A – Authority P – Principle TYPES OF WARRANTS Generalization: Whatever is true of a representative will be true of the whole group. Analogy: situations that are similar in some ways will be similar in others Sign: certain signs indicate an unobserved object or event TYPES OF WARRANTS Causality: if X occurs, then Y will follow Authority: Whatever a trusted expert says about a subject is probably right Principle: What is generally true will be true in a particular case EVALUATING LOGOS Identify and evaluate each part of the argument Main Claim Grounds Warrants Identify or Create Enthymemes Claim + Reason in one sentence EVALUATING CLAIMS Clear? Precise? Properly Qualified? Fully supported by grounds EVALUATING GROUNDS AND WARRANTS A – Appropriate B – Believable C – Consistent and Complete S – Sufficient T – Typical A – Accurate R – Relevant LET’S PRACTICE: CREATING ENTHYMEMES With a partner, come up with at least seven enthymemes (claim+reason). Write these legibly on a piece of loose-leaf paper (separate page from your notes) with both partner’s name at the top. IDENTIFYING WARRANTING ASSUMPTIONS Trade your list with another pair. Write both names under first pair’s names. Identify the warranting assumption for each enthymeme. (Write these directly on their page). Name the type of each assumption (GASCAP).
