All and All Relationship

[sohaatiq]

Hi!,

At the end of the chapter the formal logic table states that an All and All relationship can sometimes lead to inferences, could you provide an example of when an All and All relationship could not lead to an inference? I'm having a hard time conceptualizing a situation where it could not.

Thanks,
Soha

[Jeremy Press]

Hi Soha,

The relationship that would not lead to an inference would involve the following two "all" statements:

• All A's are B's.

• All C's are B's.

A real-world illustration would be: "All dogs are mammals. All whales are mammals." We can't create any definite quantitative inference (whether "all," "most," or even "some") about the relationship between dogs and whales.

I hope this helps!