Phil. 1: Introduction to Logic

University of San Diego

Schedule

Lawrence M. Hinman, Ph. D.

Answer Key

Exercise 5.3

Part I

1. All M are P.

All M are S.

All S are P.

Invalid

Illicit minor

2. Some P are M.

All S are M.

Some S are P.

Invalid

Undistributed middle

3. No M are P.

Some S are M.

Some S are not P.

Valid

No rules broken.

4. All P are M.

All S are M.

Some S are P.

Invalid

Undistributed middle;

existential fallacy

5. Some M are P.

No S are M.

Some S are not P.

Invalid

Illicit major

6. No P are M.

Some M are not S.

Some S are not P.

Invalid

Exclusive premises

7. No M are P.

All S are M.

All S are P.

Invalid

Drawing aff. concl.

from from neg. prem.

8. All M are P.

Some M are S.

Some S are P.

Valid

No rules broken.

9. All P are M.

All M are S.

Some S are P.

Invalid

Existential fallacy

Valid if P exists.

10. Some M are P.

All M are S.

Some S are not P.

Invalid

Illicit major; drawing

neg. concl. from aff.

premises

11. All P are M.

Some S are M.

Some S are P.

Invalid

Undistributed middle

12. All M are P.

Some M are S.

Some S are not P.

Invalid

Illicit major;drawing

neg. concl. from aff.

premises

13 All P are M.

No M are S.

No S are P.

Valid

No rules broken.

14. No P are M.

All M are S.

No S are P.

Invalid

Illicit minor

15. No M are P.

All M are S.

Some S are not P.

Invalid

Existential fallacy

Valid if M exists.

16. No M are P.

No S are M.

No S are P.

Invalid

Exclusive premises

17. No M are P.

All S are M.

No S are P.

Valid

No rules broken.

18. Some M are not P.

All M are S.

Some S are P.

Invalid

Drawing aff. concl.

from a neg. premise

19. All P are M.

Some S are not M.

Some S are not P.

Valid

No rules broken.

20. No M are P.

All S are M.

Some S are not P.

Invalid

Existential fallacy

Valid if S exists.

 

 

Part II

1. Some N are C.

Some C are O.

Some O are N.

Invalid

Undistributed middle

2. No I are P.

All C are P.

No C are I.

Valid

No rules broken.

3. No E are C.

All S are E.

Some S are not C.

Valid, since S exists.

4. Some C are not M.

No C are I.

Some I are not M.

Invalid

Exclusive premises

5. All T are H.

All T are E.

Some E are H.

Invalid

Existential fallacy

6. All M are P.

All M are L.

All L are P.

Invalid

Illicit minor

7. No S are V.

Some W are V.

Some W are not S.

Valid

No rules broken.

8. All W are P.

Some P are I.

Some I are W.

Invalid

Undistributed middle

9. All I are P.

Some E are not P.

Some E are I.

Invalid

Drawing aff. concl.

from a neg. premise

10. All S are M.

All M are P.

Some P are S.

Valid, since S exists.

 

Part III

1. False

2. True

3. True

  1. True

5. True

6. False

7. False

8. True

9. False

10. False

Exercise 5.3

Part I

1. All M are P.

All M are S.

All S are P.

Invalid

Illicit minor

2. Some P are M.

All S are M.

Some S are P.

Invalid

Undistributed middle

3. No M are P.

Some S are M.

Some S are not P.

Valid

No rules broken.

4. All P are M.

All S are M.

Some S are P.

Invalid

Undistributed middle;

existential fallacy

5. Some M are P.

No S are M.

Some S are not P.

Invalid

Illicit major

6. No P are M.

Some M are not S.

Some S are not P.

Invalid

Exclusive premises

7. No M are P.

All S are M.

All S are P.

Invalid

Drawing aff. concl.

from from neg. prem.

8. All M are P.

Some M are S.

Some S are P.

Valid

No rules broken.

9. All P are M.

All M are S.

Some S are P.

Invalid

Existential fallacy

Valid if P exists.

10. Some M are P.

All M are S.

Some S are not P.

Invalid

Illicit major; drawing

neg. concl. from aff.

premises

11. All P are M.

Some S are M.

Some S are P.

Invalid

Undistributed middle

12. All M are P.

Some M are S.

Some S are not P.

Invalid

Illicit major;drawing

neg. concl. from aff.

premises

13 All P are M.

No M are S.

No S are P.

Valid

No rules broken.

14. No P are M.

All M are S.

No S are P.

Invalid

Illicit minor

15. No M are P.

All M are S.

Some S are not P.

Invalid

Existential fallacy

Valid if M exists.

16. No M are P.

No S are M.

No S are P.

Invalid

Exclusive premises

17. No M are P.

All S are M.

No S are P.

Valid

No rules broken.

18. Some M are not P.

All M are S.

Some S are P.

Invalid

Drawing aff. concl.

from a neg. premise

19. All P are M.

Some S are not M.

Some S are not P.

Valid

No rules broken.

20. No M are P.

All S are M.

Some S are not P.

Invalid

Existential fallacy

Valid if S exists.

 

 

Part II

1. Some N are C.

Some C are O.

Some O are N.

Invalid

Undistributed middle

2. No I are P.

All C are P.

No C are I.

Valid

No rules broken.

3. No E are C.

All S are E.

Some S are not C.

Valid, since S exists.

4. Some C are not M.

No C are I.

Some I are not M.

Invalid

Exclusive premises

5. All T are H.

All T are E.

Some E are H.

Invalid

Existential fallacy

6. All M are P.

All M are L.

All L are P.

Invalid

Illicit minor

7. No S are V.

Some W are V.

Some W are not S.

Valid

No rules broken.

8. All W are P.

Some P are I.

Some I are W.

Invalid

Undistributed middle

9. All I are P.

Some E are not P.

Some E are I.

Invalid

Drawing aff. concl.

from a neg. premise

10. All S are M.

All M are P.

Some P are S.

Valid, since S exists.

 

Part III

1. False

2. True

3. True

  1. True

5. True

6. False

7. False

8. True

9. False

10. False