Copyright © 1997, Norman Swartz
Department of Philosophy
Simon Fraser University

Answers to the
First Set of Practice Exercises
on Necessary Conditions and Sufficient Conditions

1. true
   
   
2. false
   
   
3. false
   
   
4. true
   
   
5. true
   
   
6. false
   
   
7. false
   
   
8. true

9. false
   
   
10. false
    
    
11. false
    
    
12. false
    
    
13. true
    
    
14. false
    
    
15. false
    
    
16. true

17. false  (A chimpanzee, for example, may have two arms, but it is not a human being.)
    
    
18. false  (A war veteran may have lost both his arms, but he is a human being even so.)
    
    
19. false  (A person may want to win a foot race, but his/her wanting to do so, does not guarantee he/she can or will do so.)
    
    
20. false  (A person may do something without wanting to do so, e.g. without wanting to hurt another's feelings, we sometimes do.)
    
    
21. true*
    
    
22. true*