Hi everyone,

In the process of trying to create a summary of invalid vs. valid argument forms, I stumbled across a form that I noticed hadn't been identified as valid or invalid in the curriculum.

A ---> B

B --m-> C

---

A --s-> C

List method:

ABC

ABC

ABC

AB

AB

I know that if I were to conclude that A -m-> C it would be considered invalid (this is invalid argument form 4). I tried using the list method to check whether the "some" conclusion could be drawn and it seems valid but I'm starting to doubt I did it correctly. The closest we have in the curriculum is valid argument form #5: A--m-->B-->C. Would greatly appreciate any help in clearing this up. Don't have any background in lawgic beyond 7sage so this section of the lessons seems to be giving me the most trouble.

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3 comments

  • Monday, May 23 2016

    No problem, I just asked the right question. You did all the work:)

    1
  • Monday, May 23 2016

    @jhaldy10325 Ah! Got it. I was on the thought process of some = at least one, but my mistake was that I kept assigning the C's to the B's attached to A which doesn't necessarily have to be the case. Thank you so much.

    1
  • Monday, May 23 2016

    Try this: what if there is only a single A and 10 Bs? Run list method again and see if it's possible to force A some C to be invalid.

    1

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