INVALID Argument Forms

Question 1

TO BE INVALID MEANS…

Answer 1

EVEN IF THE PREMISES ARE TRUE, THE CONCLUSION DOES NOT HAVE TO BE TRUE

Question 2

A –> B

Answer 2

FORM 1: AFFIRMING THE NECESSARY

B
_________
A

All Jedi use the Force. Dooku uses the Force. Therefore, Dooku is a Jedi.

**THIS IS INVALID BECAUSE IT IS UNKNOWN WHAT ELSE COULD BE IN THE JEDI CATEGORY

Question 3

A –> B

Answer 3

FORM 2: DENYING THE SUFFICIENT

/A
_________
/B

All tragedies are sad. I’m not a tragedy. Therefore, I’m not sad.

** INVALID BC SAD IS NOT CONDITIONAL UPON TRADGEDY

Question 4

A –> B some C

Answer 4

FORM 3:
________
A some C

All dogs are cute. Some cute things are lovable. Therefore, some dogs are lovable.

Question 5

A –> B -most-> C

Answer 5

FORM 4:
_________
A -most-> C

All A’s are B’s. Most B’s are C’s. Therefore, most A’s are C’s

Question 6

A some B some C

Answer 6

FORM 5:
_________
A some C

Some A’s are B’s. Some B’s are C’s. Therefore, some A’s are C’s

Question 7

A -most-> B -most-> C

Answer 7

FORM 6:
_________
A some C

Most A’s are B’s. Most B’s are C’s. Therefore, some A’s are C’s

Question 8

A -most-> B some C

Answer 8

1 CORROLARY TO FORM 6

_________
A some C

“some” is weaker than “most”

Question 9

A some B -most-> C

Answer 9

2 CORROLARY TO FORM 6

_________
A some C

“some” is weaker than “most”

Question 10

A some B

A some C

Answer 10

FORM 7:
_________
B some C

Some A’s are B’s. Some A’s are C’s. Therefore, some B’s are C’s

EXACT SAME AS FORM 5 BECAUSE “SOME CAN BE REVERSIBLY READ