Which of these statements are believable??

a) "All of my 5-legged dogs can fly."
b) "I have no 5-legged dog that cannot fly."
c) "Some of my 5-legged dogs cannot fly."
d) "I have a 5-legged dog that cannot fly."

I think its (a) and (d), but im not sure. thanks.

2. Originally Posted by demon1
Which of these statements are believable??

a) "All of my 5-legged dogs can fly."
Let me do the first one.

It is saying "If there is a 5-legged man, than he flies."

THe conditional is always false.

Thus, the statement is always true.

3. Originally Posted by demon1
Which of these statements are believable??

a) "All of my 5-legged dogs can fly."
b) "I have no 5-legged dog that cannot fly."
c) "Some of my 5-legged dogs cannot fly."
d) "I have a 5-legged dog that cannot fly."

I think its (a) and (d), but im not sure. thanks.
a) As you cannot producea 5-legged dog which cannot fly as evidence
against it. Alternativly this claims that the null set is a subset of the null set.

b) Same as the first reason in a).

c) and d) are not beleivable unless you can produce a five legged dog. That
is they assert that the set of five legged dogs is non-null.

RonL