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Comment by _alternator_ | Hacker News Reader

Two mild concerns: first, I missed one and it told me I didn’t miss any at the end.

Second, some of the logic problems have flawed premises (eg All licensed pilots must pass a medical exam. Jake is a licensed pilot, therefore Jake passed a medical exam.) If you see the flaw in the premise (it assumes no fraud) then the conclusion does not follow.

Im not sure you’re going to be able to actually improve human discourse this way. The idea that it’s ‘irrationality’ that’s the source of xitters problems is far too shallow to really make a change.

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I took the pilot one as an abstract logic type question where you're supposed to assume the premise is true, so I said yes and the page said I was right, because that's a "valid logical deduction" or something.

Then there was another question in the same format that said "if you study hard enough you'll pass the exam. You didn't pass, so you didn't study hard enough." So I thought, oh, another logic one, and said yes to that one too, but the page was like, "not quite! You might fail for other reasons!"

And if, as OP says, it’s necessity and sufficiency we’re testing—whether or not there were also other reasons contributing to your exam failure, wouldn’t failing that one necessary condition be sufficient to fail the outcome?

It was the same kind of logic question. You missed a key word in your quote. I think it said “If you study hard enough you _can_ pass the exam”. It was there to make it clear that studying hard is not a guarantee for passing the test, and therefore can’t be used as the certain reason for failure.

> If you see the flaw in the premise (it assumes no fraud) then the conclusion does not follow.

Right. Or he could've been grandfathered in.

But more basically: this is logically valid, but not logically sound. These are two different ways in which something may be "true" or "false", and in this format, it's not completely clear, soundness vs validity. Based on context clues like the absurd premise of pilots -> medical exam, I assumed validity, but it's still a weird format.

Yes, I also assumed an imperfect system with cases of fraud for the medical exam question and was quite surprised by the overly simplistic response.

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