Conditionality

hihihi9993hihihi9993 Member
edited October 2017 in Logical Reasoning 342 karma

"All that is needed to save the koala is to stop deforestation"...
How would you write it as conditionality?
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SAVE KOALA --> DEFORESTATION......? (Since ALL indicates sufficiency whereas IS indicates necessity)
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I am getting confused because of this LR question where I need to pick an answer choice that contradicts the statement written above. The correct answer is "deforestation is stopped and the koala becomes extinct", which is not a negation but a contrapositive of "SAVE KOALA --> DEFORESTATION". How can it be a contradiction when it is just a mere restatement of the stimulus?
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This is from PT2.S2.Q11
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Thank you in advance

Comments

  • acsimonacsimon Alum Member
    edited October 2017 1269 karma

    Stop deforestation--> save kbear

    Your original statement can be true (in English) even though the following could also be true:

    Kbears could also be saved by transferring a sizable population to reserve X.

    However, your formalization would have it that this second statement isn't consistent with first.

    Seems you formalize a statement like this:

    Kbears will be saved only if deforestation is stopped.

    Or

    Deforestation must be stopped if kbears are to be saved.

    It is clear that these statements differ in meaning from the statement you offer.

    Just continue working through the conditionality modules and I think that that will eventually help with parsing the conditionality of more esoteric locutions like "all that is needed for x is y".

    Hopefully this helps--A.c.S

  • acsimonacsimon Alum Member
    1269 karma

    By the way, the reason that that is the credited answer is because it satisfies the antecedent (sufficient condition) and falsified the consequent (necessary condition). This is exactly what must be so if material conditionals are false.

  • hihihi9993hihihi9993 Member
    342 karma

    @acsimon said:
    Stop deforestation--> save kbear

    Your original statement can be true (in English) even though the following could also be true:

    Kbears could also be saved by transferring a sizable population to reserve X.

    However, your formalization would have it that this second statement isn't consistent with first.

    Seems you formalize a statement like this:

    Kbears will be saved only if deforestation is stopped.

    Or

    Deforestation must be stopped if kbears are to be saved.

    It is clear that these statements differ in meaning from the statement you offer.

    Just continue working through the conditionality modules and I think that that will eventually help with parsing the conditionality of more esoteric locutions like "all that is needed for x is y".

    Hopefully this helps--A.c.S

    Right! So... "All that is needed for x is y" = "Y-->X"!!!!! Got it! Thank you so much for answer many questions @acsimon !

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