Logical Reasoning

PT142 · S4 · Q19 The recent concert was probably

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The recent concert was probably not properly promoted.

Evidence

Wells (a knowledgeable person on this subject) says, .

The concert did not sell out.

Conclusion

The concert was probably poorly promoted.

Evaluate

Since we see conditional logic (unless) and repeating symbols (sell out / poorly promoted each mentioned twice), we would probably try to turn this into an abstract recipe.

Premise 1: Sell out unless poorly promoted. ~PP → SO ~SO → PP

Premise 2: Concert didn't sell out. concert was ~SO.

Conclusion: Concert was probably poorly promoted. concert was probably PP.

This seems like valid logic; in fact, it's weird that the conclusion is hedging its certainly by saying "probably poorly promoted". We have a conditional rule that says, "If it didn't sell out, then poorly promoted". We know this concert didn't sell out. So shouldn't we be sure of concluding, "Thus, is was poorly promoted"?

The reason the author is softening her certainty is because we don't "know" this conditional rule of "if didn't sell out, then poorly promoted". It's not presented as a fact. It's presented as a certain opinion of Wells.

The author does trust Wells, who is quite knowledgeable on this topic, but she is also probably thinking people are sometimes wrong. Wells is probably right about this, since he is knowledgeable, and if he is right, then the concert was definitely poorly promoted. So the concert was probably poorly promoted.

Goal

If we're really on top of our game, we want to include this appeal to expert opinion as part of the way we understand the structure of this argument.

If we don't notice that layer, we'll go looking for something like this.

Premise 1: A → B Premise 2: X was B. Conclusion: X was probably A.

If we do notice that layer, we should be looking for something like this,

Premise 1: Trusted source says, "A → B" Premise 2: X was B. Conclusion: X was probably A.

19.

The pattern of reasoning in which one of the following is most similar to that in the argument above?

  1. Dr. Smith, a well-trained cardiologist,

    Bad Relationship Match Weak Evidence Match

    The conclusion has the right strength of wording (probably). It feels like a trap that it's actually re-using the wording of "not properly". Do we have a conditional premise? Kind of: performed by → patient would highly skilled probably survive surgeon Since the strength of this is "probably", it's not really a true conditional. That mismatch would be reason enough to bail. If we were still giving this answer a chance, we could want to see the other premise trigger the rule (or its contrapositive). The other premise says "patient didn't survive", so by contrapositive we could conclude "Thus, the surgery was probably not performed by a highly skilled surgeon". But the actual conclusion brings in a new idea about whether or not it was properly performed, not whether or not it was performed by a highly skilled surgeon.

    19% picked this

  2. Professor Willis, who is quite

    Weak Evidence Match

    This is pretty close, but in the original argument, the trusted source provided us with the conditional, and reality provided us with the other premise. P1: Trusted source says, "A → B" Wells says, "didn't sell out → not prop promoted" P2: X was A. Concert didn't sell out. C: X was probably B. Concert not properly promoted. In this argument, reality provides us the conditional, and the trusted source provides us with the fact. P1: contain org compounds → labeled right P2: Trusted source, "contain org compounds" C: probably labeled right.

    6% picked this

  3. Correct

    My neighbor, who is an

    Why this is right

    Just like the original argument, the trusted source provides us with the conditional, reality provides us with a fact that triggers the conditional. P1: Trusted source says, "A → B" Neighbor says, "damage → not properly noticeable repaired" P2: X was A. The wall has noticeable damage. C: X was probably B. The wall was probably not properly repaired.

    Skill tested: Parallel · how this choice captures the argument's function is the move to repeat next time.

    62% picked this

  4. The builder said that the

    Bad Conclusion Match

    The original conclusion was not saying that someone was wrong. This could still be salvageable if "builder was wrong" was the right side of some conditional they gave us, but it isn't. The only conditional we got was this: roof not damaged → repairs not needed in storm for years Since the conclusion isn't saying "thus repairs probably won't be needed for years" or saying "thus the roof was probably damaged in the storm", we know it can't match the original argument, whose conclusion was matching the right side of our conditional.

    5% picked this

  5. Professor Yanakita, who is an

    Invalid Reversed Logic

    Just like the original argument, the trusted source provides us with the conditional, reality provides us with a fact, but in this answer choice that fact doesn't trigger the conditional. It just establishes the outcome and then the conclusion makes an illegal reversal by then inferring the trigger. P1: Trusted source says, "A → B" Professor Yanakita says, "properly → find lead conducted in soil" The next premise should be saying, "We didn't find lead in the soil". And then the conclusion would say, "Thus the tests were probably not properly conducted." Instead, we get a flawed argument. P2: X was B. The tests did find lead. C: X was probably A. The tests were probably properly conducted.

    9% picked this

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