You Don’t Suck at Necessary Assumption (You Might Just Suck at LR)

Updated September 30, 2024

One of our LSAT Demon teachers made the following comment this week:

I am noticing a real aversion to necessary assumptions recently. I think it’s a bit of mob mentality because people have seen others complaining and are drinking the Kool-Aid. Debunking the NA boogeyman might be a good newsletter article.

When asked what they meant by “noticed an aversion,” they added:

It seems like every time a necessary assumption question comes up, I get a bunch of messages in the chat like “I NEED HELP WITH NA” or “I AM SO BAD AT NA” … and these are almost always coming from people who are simply not reading slowly and carefully enough to completely understand the argument, so they can’t ID a necessary assumption when it shows up in the answer choices. I don’t think the problem is a struggle with the question type. I think it’s that the question type comes up a lot at medium/high difficulty, and they’re not understanding the argument.

Totally.

In other words, these students don’t suck at necessary assumptions. Not specifically, anyway—they might just suck at logical reasoning more broadly.

Necessary Assumption questions sound like, “Which one of the following is an assumption on which the argument depends?” or, “The argument assumes which of the following?”

The proper analysis on this type of question is simply, “What does the author have to agree with?”

But the game is almost always won or lost before we even get to that point.

The game, as always, is to attack the argument.

Imagine the following argument:

Nathan loves super burritos. Nathan is overweight. Super burritos are as big as your head and loaded with al pastor, cheese, carbs, sour cream, guacamole, and all manner of other calorie-dense shit that tends to make people overweight. Therefore, super burritos are the reason Nathan is overweight.

This argument sounds reasonable. My love of super burritos could, indeed, be the reason I’m overweight. But if you steam ahead into the question and (God forbid) the answer choices, you’ve already failed.

Your job is to disagree.

Before reading the question or the answer choices, you need to find a way to disagree with the argument.

Don’t argue with the premises. Accept the fact that I love super burritos. Accept the fact that I am overweight. Accept the fact that super burritos are loaded with all manner of calorie-heavy shit that has a tendency to make people overweight.

Do argue with the conclusion. The game on LSAT logical reasoning is to find a way to argue with the conclusion while granting the premises as true.

Is it possible that Nathan loves super burritos, super burritos make people fat, Nathan is fat, and yet super burritos are not the actual cause of Nathan’s fatness?

Imagine you’re an attorney representing the super burrito lobby. Can you grant all of the evidence in this case, while still getting your client off the hook?

Feel free to think creatively. Don’t get caught up in some LSAT nerd-mode panic over technicalities like “this is a Necessary Assumption question, omg I suck at these, I need to look for a necessary assumption here, so I’m looking for something the author must agree with…” Remember we haven’t even read the question yet. We’re still just attacking the argument.

The game is to attack the argument. Your job is to disagree. Be creative!

What if Nathan loves super burritos, but he hasn’t ever actually eaten one? Wouldn’t that get your client, the super burrito lobby, off the hook? Of course it would. So anyone trying to prove that “Nathan is fat because of super burritos” must necessarily agree with the statement, “Nathan actually eats super burritos sometimes.”

What if Nathan just bought himself a whole-ass ice cream maker, of all the stupid things for a fat person to buy, and now eats about 4,000 calories of ice cream every night? Wouldn’t that get your client, the super burrito lobby, off the hook? Yep. So anyone trying to prove that “Nathan is fat because of super burritos” must necessarily agree with the statement, “Nathan isn’t fat solely because of the 4,000 calories of homemade ice cream he eats every night after stupidly buying an actual goddamned ice cream maker on Amazon.”

What if Nathan is sedentary, because all he does is play Gloomhaven and Xcom, and all sedentary video game players are overweight?

What if he drinks too much beer?

What if he feels like Ben works out enough for both of them, and he’s trying to restore balance to the universe by never exercising and eating pizza for breakfast?

All of these things are excellent weakeners. Therefore, the argument necessarily assumes the opposite of these things.

The argument, “Nathan is overweight because of super burritos,” necessarily assumes each of the following:

• Nathan isn’t overweight because all he does is play Gloomhaven and Xcom, and all sedentary video game players are overweight.
• Nathan isn’t overweight because he drinks too much beer.
• Nathan isn’t overweight because he feels like Ben works out enough for the two of them, and he’s trying to restore the balance of the universe by never exercising and eating pizza for breakfast.

The game is won or lost, regardless of question type, by attacking the argument first.

Every potential attack on an argument can be turned into a necessary assumption.

You need to get better at attacking the argument and phrasing objections before you even read the damn question.

If you think you suck at Necessary Assumption questions, you’re probably not attacking the argument in the first place—which means you actually just suck at LR.

But you can get better! I hope you’ll view this as an opportunity, not a curse. At LSAT Demon, we’re in the business of helping people learn to do the LSAT on offense instead of defense. Once you learn to do this properly, you’ll start predicting the answers all over the place—often, before you even read the questions.