How To Do 69 Properly

Prepare for the LSAT or discuss it with others in this forum.
User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Wed Jul 31, 2013 5:52 pm

KD35 wrote:Title 180.
Topic 150.

Hm. Are you saying that the posts are 150, or that you scored 150 on 69?

If it's the former, I'm sorry you're not 99% stoked about my choice of topic.

Help me make it better!

What would you like to read more about?


User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Fri Aug 02, 2013 4:31 pm


You know what's awesome? Bait and switch LSAT argumentation, that's what's awesome. Also, politicians.

Check out how this douche nozzle (seriously. This guy's as bad as this guy--who, by the way, was really funny (Carlos Danger? Best pseudonym EVER), so that I think it's really too bad that he's apparently awful as a human being. But wait, now I've gone too far afield. Where was I?) oh, yeah; this politician baits the hook by claiming that films are causing children to hurt other children, but then when it comes to providing evidence, he switches over to show us children hurting clown dolls(!).

Now, don't get me wrong; clown dolls are irredeemably creepy and should certainly be punched (and kicked, too. While they're down. Disgusting creepy-ass things). Still, showing that children punch a clown doll does nothing at all--at ALL-- to show that children punch other children!

This horrible politician (almost certainly a member of the US Congress, amirite?) has simply assumed, without providing any evidence, that punching clown dolls means that you punch other children.

We've been asked to weaken this argument, so we'll do so by attacking that assumption.

Check out the bulge in answer choice (C)! I mean, if you say that the kids are no more likely to hurt other children, then you punch right through the false equivalence the politician set up; his assumption (that clown dolls = children) dies, and with it, his whole argument.

Yeah for the awesome power of logic!

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Tue Aug 06, 2013 6:09 pm


Behold the awesome power of recognition (in which we circumvent the process of analysis by speedy categorization by type).

The causal flaw, as astute and keen-eyed visitors to this space well know, is the single-most-commonly committed error of reasoning on the test, by my count.

Here again, it rears its ugly head, and we will dispatch it with verve and a bit of dash.

We remember that there are three main ways that the causal flaw manifests; each of them is really a version of this assumption: That there wasn't any other cause for the effect.

1. Vanilla, no-other-cause-iness: The plain assumption that there wasn't something else that brought about the phenomenon (My pants are too tight, which I blame on my haberdasher's erroneous measurements. Maybe. Maybe bad measuring caused the pants to come out too tight. Then again, it might be the case that there's some other cause. Maybe I've been going pretty heavy on the Neverending Pasta Bowl at my local pit of gluttony and of sadness Olive Garden Family Restaurant. Until I rule out my fatness as a cause, I can't blame the poor fit on my tailor).

2. Coincidence-as-cause-ishness. The assumption that the relationship between the two events was not just a coincidence (Home prices in my neighborhood have increased by nearly 10% since I moved in. Have the neighbors learned of my awesomeness and begun trying to cash in by selling their homes at a premium? Maybe. Maybe prices increased because I'm awesome. Then again, maybe the price increase had nothing to do with my recent move; the two events could be correlated without having any causal relationship. We can't say it was me that caused it until we rule out the possibility of coincidence).

3. Reverse-cause-ocity. The assumption that the causal relationship was not actually the other way around (Numerous studies have shown that nebbishy guys who marry supermodels are rich. Since I'm pretty nebbishy and desperately want to be rich, I will therefore figure out how to marry a supermodel. Boom. PROBLEM SOLVED. Again, maybe. Maybe marrying a supermodel somehow causes wealth. Then again, it may just be the other way around; maybe it's because they are rich that these nerds marry the supermodels. We can't say thing A caused thing B until we've ruled out the possibility that thing B instead caused thing A).

Here, we've claimed that the earthworm has caused the extinction of the goblin fern, because in places where there's less leaf litter, you find more earthworms and fewer goblin ferns. But do you see the possibility of another explanation? Yeah, me too.

So, yeah, maybe. Maybe the earthworm is causing the extinction, as this argument has claimed. But then again, maybe it's the other way around; maybe the disappearance of the goblin fern makes an area more attractive to earthworms.

In order to conclude that thing A (earthworms) causes thing B (extinction), we have to rule out the possibility that it's the other way around. In other words, to say the earthworms are the culprits is to assume that they do not move into an area as a result of the lack of goblin ferns.

Now check out answer choice (E)!


And also, seeing as this is a Necessary Assumption question, don't forget to perform your negate test; if (E) isn't true, and if worms actually do prefer to live where there are fewer ferns, then our argument becomes stupid; earthworms didn't cause the extinction, they were just attracted by it after it had already happened.

Boom. Problem solved.

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Wed Aug 07, 2013 8:20 pm


Hey, you remember how last time we were here (i.e., yesterday), I told you that the causal flaw was, by my count, the single most commonly-committed error in reasoning on the LSAT?

Did that—even for a moment—make you think that most of the arguments in the Logical Reasoning exhibited that flaw?

Of course not, because you are awesome, and thoughtful, and furthermore, equipped with strong evidence to the contrary.

In exactly the same way that if I told you that October 5th was the most common birthday in the US (which it evidently is, if I am to believe the interwebs), you wouldn't take that to mean that most of the people in the US were born on October 5th. That would be stupid; only about 1 million people, or roughly one-third of one percent of Americans, were born on that date.

So it's clear that just because something is most common does not mean that it's a majority.

To confuse those two concepts is to commit an error of reasoning I like to call Proportion Confusion. It's to conflate a proportion (the most common birthdate) with a real number (the birthdate of a majority of people).

Now, let's see this shizz in action on an LSAT question.

In Q 20 here, the medical reporter tells us that heart disease is one of the most common forms of disease, and then claims that preventing it would therefore help most people. AND THIS IS THE SAME THING WE WERE JUST TALKING ABOUT!

Just because it's the most common by proportion doesn't mean heart disease afflicts a majority; maybe it afflicts just 0.3% of people, but maybe every other disease involves even fewer people than that.

So the big idea, here, again is to sidestep the analysis by means of recognition. Whenever you see mention of any kind of proportion, you ought to ask yourself, "Hey, man; how are they using this proportion to try (vainly) to trick me?".

And check out answer choice (B)—if you bring up the possibility that even if a disease is most common, it still doesn't mean most people have it—then you point out the flaw of the argument, by pointing out that its assumption (that a proportion does tell you about a real number) is false.

And that, as the fellow said, is that.

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Tue Aug 13, 2013 12:31 am


Good god I love it when a plan comes together.

Just two posts ago—and literally FIVE questions ago on the test as administered—we saw an example of the causal flaw. Specifically, the assumption that the causal relationship wasn't actually operating in reverse. And now, just five questions later, WE'RE SEEING THAT SAME SHIT ALL OVER AGAIN.

You'd be quite forgiven at this juncture if you were to roll your eyes at the test writers, say "Really? Is this all you've got?" and drop the mic.

Here, we're told that that bastion of killjoy-iness, the Department of Health, has asked a bunch of 17-year-olds to take a pledge not to drink. Then, to their delight, they found that most of the kids who took that pledge didn't drink! And from this, they've concluded that their pledge works; they've claimed that the pledge is keeping the kids off the Purple Drank.


But then again, it's really super easy to take a pledge not to do something that you know you're not going to do anyway.

Like this:

I solemnly pledge never to vote for Justin Bieber for any elected office. Ever. I mean, never, ever. Not even a little.

I further pledge that I will not mix the lime with the coconut and drink them both together.

I also pledge that I will not get a tattoo of a butterfly on the small of my back. Or anywhere at all.

I pledge not to wear a mankini to the beach. Or anywhere at all.

I pledge not to wear Axe body spray.

I pledge not to order an appletini to drink.

I pledge not to stop eating just because I'm full if I'm at a buffet (I mean, come on).

I pledge not to drive a Hummer.

I pledge not to pants my grandpa.

I pledge not to pants your grandpa.

And, I mean, I could go on, but you probably get the point.

So, yeah, the kids that took the pledge didn't drink, but it's possible that they took the pledge BECAUSE they didn't drink. Like every argument that posits a causal relationship, this one fails because it just assumes that there was no other cause; specifically, this argument assumes that the cause was not running the other way.

And, of course, we get answer choice (C) to neatly sum up that flaw in the kind of delightful language only a test writer could love.


User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Tue Aug 27, 2013 2:55 pm


The re-re-return of the causal flaw.

Just when you thought you'd seen the last of the causal flaw in a section.

I mean, maaan. Just when you think the section has gracefully ended its causal-flaw-career like the tween star of a Disney afternoon show heading quietly into obscurity doing bland corporate pop songs... BOOM! There it is again, this causal flaw, dressed in a strange half bear suit, singing bland corporate pop, sure, but TWERKING ALL OVER YOUR FACE with its tongue wildly trying to escape its mouth the whole time.

Oh, causal flaw, what would your daddy think of your strange public liaise-ing with a creepy older flaw that couldn't dance his way out of a soggy paper bag? Also, why the foam finger? Just why?

But we digress.

So, question 23 is a Method question. Notice that the question type has nothing to do with whether an argument has exhibited a typical flaw; this arguer points out for us the causal assumption espoused by some researchers. Those dummies say that the cause of our taboos is practical considerations (you don't eat your dogs because they are useful for fetching sticks for you), to which this arguer says, "Well, maybe..."

But, then again, she points out, the causal relationship may have run the other way. Maybe we actually stopped eating dogs because of religion or superstition or whatnot, and then the practical uses arose later ("Well, now that we've stopped eating dogs we've got all these excess dogs running around. Do you think we can teach them to twerk? No, you're probably right. But we could make them start fetching our sticks for us, though").


No. That's not the point. This is the point: If you can recognize the causal flaw whenever it occurs, then your job in this question becomes much easier and faster. You read the passage and describe it quickly by saying to yourself "This author has pointed out the causal assumption, and provided an alternate causal explanation". When you're able to get that description in hand, your assessment of answer choices becomes a simple match game.

Now if you'll excuse me, I have some Disney shows to not watch.

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Wed Aug 28, 2013 8:23 pm


You know what a syllogism is?

Don't worry; it's only maybe 30% as filthy as it sounds (you know, as I think about it, it's possibly even less than that).

A syllogism is a particular form of argument comprising three parts:

1. A major premise. This is a rule. It's a broad, sweeping statement covering all cases.

2. A minor premise. This is the fact at hand; it tells us about an instance in front of us.

3. A conclusion. This combines the major and minor premise into a claim about the fact at hand.

Let's take a look at an example.

Every orgy leads to feelings of self-loathing and recriminations in its participants the morning after. Since Mildred is known to have been involved in the "Swingin' Senior" orgy organized by the Final Rest Nursing home last night, she must be feeling self-hatred this morning.

Here, the first sentence is our Major Premise; it gives a rule that applies to all orgy-goers. The first half of the second sentence is our Minor Premise; it tells us that Mildred belongs to the universe of orgy participants. The last half of that sentence combines the two premises into the properly-supported conclusion that Mildred must be feeling bad today.

Here's why that's useful; a huge number of Sufficient Assumption questions operate by presenting you an argument that offers two-thirds of a syllogism (usually the minor premise and the conclusion) and then asking you to add evidence to prove the conclusion. So you know what you're going to add: the missing Major Premise!

If our argument above had appeared on the LSAT, we'd expect it to have taken a form something like this:

Mildred must be feeling some self-hatred this morning. After all, she's known to have the sexual appetites of a woman a quarter her age, having done the horizontal mambo with Stanley, been rumored to have made the beast with two backs with Fred, bumped uglies with Eunice, and coitused Melvin on at least two occasions, so it came as no surprise to find that she was involved in the "Swingin' Senior" orgy organized by the Final Rest Nursing home last night.

See how we've still got our conclusion, only now it's at the beginning, and then a bunch of noise (to be expected) before we get to our only real evidence; that Minor Premise. If this argument came with a Sufficient Assumption question, we could expect the correct answer to supply the missing Major Premise, like this:

(A) Every orgy leads to feelings of self-loathing and recriminations in its participants the morning after.

And if we recognize this pattern, our work becomes faster and more-efficient overall.

Consider question 25. Notice that it conforms pretty neatly to this paradigm.

The argument tells us a bunch of crap leading to the Minor Premise that folktales provide insight into a culture's wisdom. This evidence is offered in support of the claim that folktales do have deep meaning.

And we've been asked to prove that conclusion is true. Can you see how we'll do it by providing the missing Major Premise? We can expect an answer that says something like "Everything that provides insight into a culture has deep meaning" - just like in the Mildred example above.

And sure enough, (B) says exactly that—in almost those words precisely.

Awesome, huh?

Now, if you'll excuse me, I have some mental images I need desperately to unsee.

User avatar

Posts: 36
Joined: Wed Jun 27, 2012 8:35 pm

Re: How To Do 69 Properly

Postby MauveT-Rex » Wed Aug 28, 2013 10:21 pm

That's a great pattern to look for in Sufficient questions, I had never really internalized it that way before. I had also never given so much thought to senior orgies also. Thanks for the former and not so much for the latter....

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Thu Aug 29, 2013 4:26 pm

MauveT-Rex wrote:That's a great pattern to look for in Sufficient questions, I had never really internalized it that way before. I had also never given so much thought to senior orgies also. Thanks for the former and not so much for the latter....

Yeah, the thought pretty much burns my eyes out. Sorry about that; if there were any other way to talk about Sufficient Assumptions, believe me, I would've.

But my hands were tied.

User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Wed Sep 04, 2013 2:25 am


And now comes the time in our studies when we need to talk about the word "consistent."

You know what that word means? Almost nothing, is what it means. Seriously, it has barely any meaning at all. Like this:

Wearing women's underwear is consistent with being a scary, stalkery creeper.

Of course, wearing women's underwear is also consistent with being a totally normal and lovely woman.

Sniffing glue is consistent with being a brain-dead sociopath.

Then again, sniffing glue is also consistent with being a bright and inquisitive puppy.

Kissing your boss on the lips is behavior consistent with a pink slip and also possibly a restraining order.

However, kissing your boss on the lips is also behavior consistent with being your boss's husband.

See what I mean? Consistency has no currency; that two things are consistent with each other means only that they are not mutually exclusive.

And now perhaps you can see where this is going; while consistent has almost no meaning, inconsistent means a whole big fat lot.

If two things are inconsistent, then those things are mutually exclusive. They cannot both happen at the same time and place.

Being in Boston at a certain time is inconsistent with being in Damascus at that time.

Wearing Crocs is inconsistent with enjoying a wide dating pool.

And so on.

So in this question, when we are asked what is inconsistent with the rule outlined in the passage, we are being asked for an answer that must be false, according to that rule.

In this case, the rule is (as it always is) a simple conditional: You can't restrict behavior unless you're preventing harm to others.

(I'm sure you remember how to deal symbolically with "unless", but if you need a refresher, here's a video recap).

When we're done, we should have this:

R[estrict/Interfere] → P[revent harm to others]

or, contrapositivize that bitch:

not-P[reventing] → no-R[etricting]

Among the answer choices, we may expect some wrong answers that follow the rule, and some other bad choices that just live outside the rule altogether (I'm especially looking at you, (B) and your scientist nonsense).

Then there will be one correct choice that directly violates the rule. Here, to be inconsistent we need an instance where we do restrict behavior, even though that restriction doesn't prevent harm to others.

And in answer choice (E), we're going to nanny state that shit, just to keep people from harming themselves. This is inconsistent with our rule!


User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Thu Jan 02, 2014 7:49 pm

[in which we skip all the way to PrepTest 71.1.1, and also undertake to tell three jokes about bankers]

Hi, there. It's been a while since we've spoken. That's maybe because I haven't posted recently? Yep, that's definitely it.


Also, welcome to 2014! Before we move on, I just want one minute here to look back: 2013 was the best year ever for Velocity LSAT, and that's thanks to you guys. We know that we wouldn't be here without you, and we're glad that if we're going to do this whole LSAT thing, we at least get to do it together.

But enough about us. Let's have one of those jokes about bankers (I Googled "Jokes About Bankers" and clicked the first link. CREATIVE.)

What’s the difference between a tragedy and a catastrophe?

A tragedy is a ship full of bankers going down in a storm; a catastrophe is when they can all swim. HEY-OHH!

OK. That was fun. Now, let's cast a long, meaningful look at Question 1 from the first Logical Reasoning section of PrepTest 71, which, as it happens, is an argument about bankers.

First, note that the question here is a Sufficient Assumption question; the answer to this question will PROVE that the conclusion of the argument is true. So our goal is to prove the claim that they'll probably not strengthen the banking system (because the whole argument is set up to support that central claim; that the agency is likely not to do what it wants to do: make the banking system stronger).

Next, let's pause briefly to consider the nature of the right answer to this question. If we're going to prove that some claim is true, that's going to take us some doing. I mean, for example, just saying that SOMETIMES people who work at test prep companies are mouth-breathers isn't even close to enough to prove that if you work in test prep, you're probably a mouth-breather. If you really wanted to PROVE something, you'd not say "sometimes"; you'd be much better off saying "all the time." Because if it's really true that ALL the people in test prep are mouth-breathers, then by god anybody you've ever heard of in that industry is a moist and slobbering breather-by-mouth.

This is a principle of proof that applies broadly; the answer to all your Sufficient Assumption questions is VERY LIKELY to employ this big, heavy-duty language that I call Load-Bearing Language. Expect words like ALL, NONE, EVERY, NEVER. This is a useful bit of knowledge to have in your back pocket as you begin to examine answer choices.

Now, back to the argument; we've claimed that they probably won't strengthen banks by selling them, because IF THE FORMER OWNERS BUY THEM BACK, that won't help them get stronger. So, you can see how simple it would be to prove that selling the banks won't help, right? Using our knowledge about language cues and the evidence of this argument, we could put together an answer that says that ONLY the former owners are going to buy these banks back. If that's true—if ALL the buyers are former owners, and if former owners can't strengthen banks, well, then our conclusion is true: selling these banks WON'T make them stronger.

AND CHECK OUT ANSWER CHOICE (E). This is exactly what we wanted! It's like Christmas again all of a sudden up in here.

Now, let's celebrate with two more terrible jokes about bankers, and call it a day:

What do a banker and a slinky have in common?

They’re both fun to watch tumble down the stairs. BADA-BING.

What’s the difference between a banker and a trampoline?

You take off your boots to jump on a trampoline. NO HE DINT.

Yes he did! Thank you and goodnight.


User avatar
Dave Hall

Posts: 186
Joined: Thu Jul 28, 2011 4:18 pm

Re: How To Do 69 Properly

Postby Dave Hall » Sun Jan 05, 2014 10:38 pm

71.1.2 [ he just going through PrepTest 71 in order? MAYBE]

You know how sucky it is when you're at a social gathering, and somebody's telling you an awesome story about this ninja they met in Iga, and then some other guy butts in and he's all like, "Actually, ninjutzu was started as a reaction to the showy, antiquated style of the samurai, by a former..." and you tune him out almost immediately, but while you do so, you have a vision of stabbing him in the kneecap with a fork, ninja-style? Yeah, I know. You're sitting next to THAT GUY, and that sucks. Nobody likes the guy who starts sentences with the word "actually." It has never, in the entire history of its usage, preceded any remark that wasn't douchey.

Anyway, the accountant in Question 2 is totally That Guy.

And he's doing a typical LSAT thing, where he ascribes a position to some other party just in order to refute it. Here, he's telling us what some people (the newspaper industrial complex) say about costs, in order to say that they're wrong. Why are they wrong? BECAUSE HE SAYS SO IS WHY. Because the real threats are allegedly circulation and advertising fall-offs. Maybe, but he doesn't give us any evidence of it. He just claims it, and assumes it's relevant to the discussion.

And here's why that matters: this faulty logic is a typical error in reasoning committed by the LSAT, and you'll notice that here, it doesn't come in an argument that we've been asked to attack or defend. Here, we're just asked to describe what the accountant did. But that job is easier here—as it would also be easier in a question asking us to weaken or strengthen or whatever—by the fact that we can quickly describe his reasoning by appeal to a type that we have already seen before.

I describe the accountant's argument like this: THAT GUY is saying that the newspaper people are wrong about why they're losing money, because it's... wait for it... ACTUALLY for different reasons [that may or may not be true].

From that jumping-off point, it's easy to pick (D) for its similar assessment (we used the words "why" and "reasons" where the test writers used the word "explanations." This is the kind of synonymous description we're looking for in a right answer).

So, I guess what I'm saying is this:

1. Knowing types of commonly-committed errors of reasoning is helpful for more than just identifying and exploiting flaws.

2. Answering questions before going to answer choices makes us more efficient, more correct, and more full of the smug deliciousness of self-satisfaction (yeah, I don't know about that last one. It just seemed like the structure here called for a third thing that we're more of).

3. Don't be That Guy.

Return to “LSAT Prep and Discussion Forum?

Who is online

Users browsing this forum: Google [Bot] and 16 guests