39 in logic we treat statements of the form either a

39. In logic, we treat statements of the form “Either A or B” as saying the same thing as;
A. Either A or B, or both A and B.
B. Either A or B, but not both A and B.
C. Both A and B.
D. All of the above.
40. Use argument forms to determine whether the following arguments are valid or are
fallacies. Give a reason to justify your answers.
41. Use counterexamples to show that the following arguments are invalid.
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A. If Susan is a famous author then she knows how to write. Moreover, Susan knows
how to write. So, she is a famous author.
B. If Lewis is a famous author then he knows how to write. But Lewis is not a famous
author. Hence, Lewis does not know how to write.
C. “No people whose attention is easily distracted while they are working are people
who are keenly interested in their work. No successful people are people whose
attention is easily distracted while they are working. So, all successful people are
people who are keenly interested in their work.”]
D. “All zoologists are natural scientists. No historians are zoologists. So, no historians are
natural scientists.”
E. “Some people who endanger the social order are not mean-spirited people. All
intolerant people are people who endanger the social order. Hence, some intolerant
people are not mean-spirited people.”
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