4. Attacking a weaker argument instead of the main conclusion: “What you are saying is that. . .”
5. Irrelevant authority
• Popular opinion. Most CDers think I am smart. Therefore, I am smart!
• Unqualified individuals. Since Yao Mng is a great athlete, if he says GMAT is a piece of cake, it probably is.
• Emotions.
6. Irrelevant premises
Ask yourself, “Do the premises strengthen or weaken the conclusion?” If not, they are irrelevant. Often premises will use the same words and thus appear relevant even though they are not.
7. Conflicting premise or assumptions
Example: “That family of four needs a dozen eggs to make a breakfast. Hua, the dad, did not buy enough eggs for his family because he bought only three eggs for each family member.”
At present the Hollywood Restaurant has only standard-height tables. However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities. Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables. Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.
The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that
(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available
(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals
(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering
(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer
(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall he support
8. Circular
Ask yourself, “Could the conclusion support the premises?” If so, then the argument is circular –it assumes what it is trying to prove.
