Sufficient & Necessary Questions - - Question 19

Only an expert in some branch of psychology could understand why Patrick is behaving irrationally. But no expert is c...

alicat6 June 12, 2020

S&N Questions with "No" embedded

I am still unsure how to diagram conditional sentences that have the word "No" embedded in them. For example from this question, "But no expert is certain of being able to solve someone else's problem." In my mind, I would diagram it "not E -> CSP," whereas the correct diagram is "E -> not CSP." Can you explain this further why sentences with "no" or negatives are diagrammed like this?

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shunhe June 13, 2020

Hi @alicat6,

Thanks for the question! Diagramming “no” sentences can be a bit tricky at first, and I think it helps to translate things into normal English using “if” language. Let’s take a look at your example, no expert is certain of being able to solve someone else’s problem. How would we say this in “if” language? Well, if you’re an expert, then you’re not certain of being able to solve someone else’s problem. This makes it pretty apparent that the correct diagram is E —> ~CSP. Or another, simpler example: No ice cream is hot. Again, how do we translate that? If it’s ice cream, it’s not hot. We wouldn’t interpret that as if it’s not ice cream, then it is hot. So in general, “No X are Y” are diagrammed as X —> ~Y, because it’s the same as saying “if X, then not Y.”

Hope this helps! Feel free to ask any other questions that you might have.

alicat6 June 15, 2020

This was really helpful! Thank you!

ohanamgt December 25, 2020

Awesome Shunhe!

Zikica January 3, 2021

Hello,
I don't understand why the concept of Charles is introduced?! I do understand the sentence/response structure however I have eliminated it based on Charles?

Zikica January 3, 2021

Hello,
I don't understand why the concept of Charles is introduced?! I do understand the sentence/response structure however I have eliminated it based on Charles?