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Philosophy 103: Introduction to Logic
Logic Assessment Pretest Question 10
Draft Analysis

10. What can most probably be concluded about the following argument?  If she gives you an invitation to her party, then she wants you to come. Since she didn't give you an invitation, she obviously doesn't want you to come.  a. You can logically conclude she doesn't want you to come to the party.  b. The invitation quite possibly was lost, so you can't conclude anything.  c. You can't logically conclude that she doesn't want you to come.  d. You can safely conclude if she wanted you to come, she would have given you an invitation.  e. Nothing can be concluded with certainty. Purpose for the Question:  One objective of logic is to obtain facility in symbolic manipulations and to realize that the proper use of logic is a reasonable way to solve problems. If we translate to symbols, the argument can be put as:  I -> W ~I -> ~W ---------- (conclusion)  This argument form is called "the fallacy of denying the antecedent."		Phil 103 02 Archie
		Engl 373 04 Dumont-Poston
		Engl 101 22 Westcott

Answer Choices: 

a. You can't logically conclude that she doesn't want you to come since there could be other reasons why you did not receive an invitation.

b. This answer represents only one of many possible explanations, but the reason you can't conclude anything is not necessarily that the invitation was possibly lost.

c. You can't conclude that she doesn't want you to come from the fact that you did not receive an invitation. This is the correct answer.  

d.  Answer d is the fallacy of affirming the consequent.

e.  This answer is false because, by modus tollens, one could conclude if she doesn't want you to come, she won't give you an invitation.

Evaluation:    The answers to this question are not consistent across the disciplines. The answers given could depend upon different background conditions (i.e., the ceteris paribus conditions) supposed by students in different classes. Since so many students missed the best answer, this question might be best put as a non-decisional form of implication.

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