December 2011 LSAT Section 1 Question 25

Interior decorator: All coffeehouses and restaurants are public places. Most well–designed public places feature artw...

Mazen on April 19, 2022

Diagramming the 1st Sentence

The first sentence: "All coffeehouses and restaurants are public places." I understand the difference between "and" and "or" when its comes to diagramming and how they flip when applying the contrapositive of the initial principle. However, in the case of the sentence above, I am strongly inclined to diagram it in its initial form as if it were an "or" rather than an "and." In other words, even though it states "All coffeehouses AND restaurants are public places," I read it as "All coffeehouses [or] restaurants are public places." The presence of either guarantees the presence of public places. My reasoning is coffeehouses and restaurants do not have to compound to form the sufficient condition triggering the necessary being the public place. Each element, whether coffeehouse or restaurant, is sufficient to guarantee being a public place. And the contrapositive is accordingly an "and": The absence of public places guarantee the absence of both "restaurants AND coffeehouses." I feel that formal technicality does not supersede common sense. This is not like two atoms of hydrogen AND one atom of oxygen guarantee a water molecule; in this case, we need both to guarantee the molecule. But we do not need both a restaurant and a coffeehouse to guarantee the existence of a public place. In a universe where we have all coffeehouses, we have public places; and in another where restaurants exist and coffeehouses do not, we still have public places; we do not need BOTH/AND to guarantee having a public places. Am I wrong? Please let me know!

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Naryan-Shukle on April 20, 2022

Hi @Mazen,

You are not wrong, BUT I think there are some things I will say.

First, I think the most important thing here is to realign your goal of studying this. It's very tempting to get obsessed with the logic of one particular question, and it's something every student, including myself, goes through. The faster you can get past this, the faster you can get to a high LSAT score. Don't let yourself get bogged down with minute intricacies of one particular question. If you understand the concept and know what you're doing, that's what matters.

Now...to get bogged down in this question for a minute (yes, I see the irony haha) I think your analysis is right IF you read it a certain way. The way you are reading this statement is as if there's a grammatical contraction:

"All coffeehouses AND (all) restaurants are public spaces."

If read like this with the grammatical omission of the second (all), this simply creates two separately existing chains.

CH ----> PP
R ------> PP

BUT if you read it as "All (coffee house + restaurant dual establishments) are public spaces, THEN the chain would be

CH + R -----> PP
(if you are a thing that is a coffee house and restaurant, then you are a public place)

Now, which of those two is it? The unsatisfying but true answer is it depends. If the rest of the context is talking about establishments that are both restaurant and coffee house simultaneously, then the latter is most likely the correct way to view the grammar. If the passage discusses restaurants, then coffee houses separately, the former would apply.

In the end this is why I say don't get bogged down. None of this tedious hair splitting makes you better at taking the LSAT. It sounds like you understand S&N well, so don't let this one oddity stop you from studying with confidence.

Hope this helps!

Mazen on April 20, 2022

Hi Naryan,

Thank you for your guidance and your time. Two key takeaways from your comments: first, rely one the context for interpreting to how to read a conditional; and second, interpretation of conditionals should not be treated with too much rigidity, as important as they are, once mastered trust my studying!

However, I would like an expert's input on one general observation regarding your former advice, i.e. to rely one the context for interpretation of conditionals. For the purposes of gaining reassurance regarding a general approach:

The rigidity with which we treat conditionals varies from one stimulus to another, specifically from one that is an argument (containing a conclusion and support) to one that is encompasses a statement of facts from which we make an inference (must be true answer-choice, or most strongly supported answer-choice). The reason for this is that the statements within a stimulus that is not an argument but rather a statement of facts are less relatable to one another, hence the increased degree of rigidity in the application of formal logic to them. This approach, however, is not to be executed without caveats/exception such as shared terms within the statement of facts stimuli.

I know I know I opened this response with a "don't get bogged down key takeaway" only top get bogged down with other key takeaway "context." How is that for irony!!!

Thank you Sir