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  • Posts: 2
  • Joined: Aug 31, 2020

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.

 Jeremy Press
PowerScore Staff
  • PowerScore Staff
  • Posts: 850
  • Joined: Jun 12, 2017
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!

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