If I had a nickel for every student who lost four raw points on Logical Reasoning
strictly because of the word unless, I, uh, I would be retired on a beach somewhere.
It is, it's easily the most expensive word on the test.
Four raw points.
That is literally the difference between a one sixty eight and a one seventy two.
It really is.
And it's not just unless.
It's the whole cluster of four exception indicators.
You have unless, except, until, and without.
Standard conversational English tricks your brain into negating the wrong side of
the conditional arrow every single time.
Right, because in real life, when someone says you can't eat dessert unless you
finish your vegetables, you assume those two things are just swapped around
casually.
But on the LSAT, that casual translation gets you wrecked on necessary assumption
questions.
Precisely.
So we throw out intuition and we use what we call the Unless Equation.
It is a two step mechanical rule.
Step one: whatever word or idea unless modifies becomes necessary.
That means it goes at the tail end of the arrow, after the conditional split.
Okay, whatever word or idea unless modifies becomes necessary.
Got it.
So if the sentence is, no contract is binding unless signed,
the word unless is directly modifying signed.
Exact.
So signed is your necessary condition.
It goes on the right side of the arrow.
Step two is where people hesitate: you take the remaining clause,
which is no contract is binding, and you negate it completely to make it the
sufficient condition on the left.
So the negation of no contract is binding becomes the contract is binding.
Correct.
So your diagram is simply: Binding requires Signed.
Or, Binding arrow Signed.
Which makes total sense!
But, man, when I was starting out, I remember getting totally bogged down in double
negation traps on timed drills.
I would see a statement like that, panic for five seconds, and draw a mistaken
reversal like Signed arrow Binding, which is, obviously wrong.
Just signing something doesn't automatically make it a valid contract!
Right, you could sign a napkin with crayon, doesn't make it enforceable.
The sanity check under pressure is always the contrapositive.
Take your diagram, Binding arrow Signed, flip both sides, and negate them both.
What do you get?
Not Signed arrow Not Binding.
If it is not signed, then it is definitely not binding.
Five seconds.
That contrapositive check completely eliminates the temptation to draw a mistaken
reversal when the clock is ticking down.
Okay, but Adrian, what happens when LSAC decides to be extra cruel and throw a
compound clause into the mix?
Like when they drop an or inside the unless statement?
Ah, compound exception clauses.
This is LSAC's favorite trap for students who rely on rote memory without
understanding the underlying logic.
Let's take a concrete argument.
Suppose the stimulus says: The proposal will pass unless Director Vance dissents or
Representative Ruiz abstains.
Director Vance and Representative Ruiz.
Classic board meeting drama.
Okay, walk me through the translation step by step.
Alright, apply step one of our equation.
What is modified by unless?
The entire phrase: Director Vance dissents or Representative Ruiz abstains.
So that whole chunk goes to the right side of the arrow as the necessary condition.
Right.
Now step two: negate the remaining clause, proposal will pass,
to get proposal does not pass on the left side.
So your initial setup is: Not Pass arrow Vance Dissents OR Ruiz
Abstains.
Okay, clear enough.
But the real nightmare is when you need to take the contrapositive of that compound
statement to answer a sufficient assumption question.
And that is where De Morgan's Law comes in.
When you negate a compound condition containing or, or containing and,
you have to flip the logical operator.
This is the golden rule: and becomes or and or becomes and.
Yes!
That was my huge lightbulb moment when I was studying!
And becomes or and or becomes and!
So if you negate Vance Dissents OR Ruiz Abstains, it becomes Vance does NOT dissent
AND Ruiz does NOT abstain!
Beautifully done.
So the contrapositive reads: If Vance does not dissent AND Ruiz does not
abstain, then the proposal WILL pass.
That feels so clean when you break it down like that.
But, um, how do you keep from scrambling the logic when you have like fifteen
seconds left on question twenty two?
We use what I call the Rule of Three Flips for compound conditions.
When taking the contrapositive of a compound statement, you do three distinct flips
in your mental audit.
One: flip the order of the terms from right to left.
Two: flip the negations on every individual term.
Three: flip the boolean operator itself, so or flips to and.
Three flips.
Flip terms, flip negations, flip operators.
That ten second mental checklist saved my score so many times on section four.
It works every single time.
Master the three flips, and exception clauses go from being a trap to being free
points.
Free points are my favorite kind of points.
Alright, good chatting, Adrian.
Talk soon, Nora.