Drawing Valid Conclusion Question

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  keets993 Alum Member ⭐ ⏰ 🍌

  February 2018 6050 karma

  Hey, so for the first question the reason there is no inferred relationship between /Q and Y and similarly T and /Q is because the argument form looks like this:

  /Q -> W -> /R
  -m-> T -> Y

  The relationship between /Q and T and Y is invalid. You cannot draw any conclusions from it because it's argument form 4. The reason there is a relationship with W is because that's the starting point.

  Most W's are T's and all T's are Y's.

  W -m->T -> Y
  That's a valid argument. When you have the intersectional before the all it's a valid argument. The list form always helps me.
  TY
  TY
  WTY
  WTY
  W

  We don't know anything about T except that there is an intersection with W. We know most W's are T's but we cannot definetly conclude how many T's there are in the world. All we know from the information we are given is that every T is accompanied by a Y. However, we can conclude that most W's are T and most W's are Y. When you add the /Q in front of the W, the relationship that "most /Q's are T" and "most /Q's are Y's" becomes a possibility.

  It could be that
  (Scenario 1) (Scenario 2) (Scenario 3)
  WTY /QWTY /QW
  WTY /QWTY /QW
  WTY /QW /QW
  WTY WTY
  /QWTY WTY
  /QW WTY
  /QW WTY

  Do you see here how in just these three scenario's we have a some relationship between /Q and T and Y (scenario 1); a most relationship with /Q and T and Y (scenario 2); and no relationship between /Q and T and Y? In order for a relationship to be valid it has to be true. Whereas in this it could be true, it's not the case that it must be true.

  It's a similar issue with your second question. I -> F some D is not valid because the conditional relationship is there before the existential. Try going through your valid and invalid forms again. Hope this helped and let me know if you have anymore questions. These letters become confusing if you stare at the screen too long...