Conditional Logic: You Can’t Succeed Without It

BPProbert-lsat-blog-conditional-statements

Conditional statements are at the heart of the LSAT. And that’s no surprise, really, because they’re at the heart of the law as well. If this party breaches contract, then these are the repercussions. Unless this nation comes into compliance with international law, these consequences will follow. If you do not take steps to remediate this violation of my client’s rights, we will take legal action.

While each of the above is a conditional statement, expressing what will result if a particular condition is met or unmet, the phrasing and composition varies significantly between them. The simplest form of a conditional statement involves “if” and “then,” as in “if the frosting-to-cake ration is excessive then I will scrape some off.” Here, of course, the condition of excessive sugar-whip is sufficient to necessitate that I excavate my cake. 

But what about the following conditional statement: “without a first-round running back, your fantasy team will lose”? There are no “if” or “then”s to guide us here. And yet, consider our options: is it the case that if you lose, then you are without a first-round running back? Of course not; millions of people lose their fantasy league every year despite having drafted a RB as their first pick. Instead, we phrase it as “if you don’t pick a running back in the first round, then you are destined to lose.” Meaning that if you snatch up Odell Beckham first just because he’s on the cover of Madden, you’re starting off in bad shape.

These questions, of course, pop up all over the place in Logical Reasoning. All your Must Be True questions will include conditional statements: variations of “if A then B.” Your Flaw questions will often require that you identify a misapplication of sufficient and necessary principles: did the argument confuse what is required with what is simply adequate? Assumption questions take the concept out of the modular scale and apply it to the argument as a whole: which of the following assumptions is sufficient to make the argument’s conclusion follow? Which of the following assumptions is necessary in order for the argument to hold up?

But the concept is just as important in Logic Games, where you’ll find countless examples of Allen obstinately refusing to attend the bar mitzvah unless Renzo goes, and Andrew’s piano recital following Katherine’s if and only if Muqeem’s mauve dinosaur eats the marzipan portion of Spencer’s seven-layer cake. Add to that the conditionals you’ll encounter all through law school and then over decades of practice, and you can see why we put such an emphasis on these concept in our courses.

Questions, comments? Stuck on a tricky conditional question? Post below!

2 Responses

  1. Joy says:

    Hi! So I am going through the Kaplan LSAT prep book. I have a good understanding of translating conditional statements, but there are the few tricky ones that I’m not getting. I fear those are the ones I would lose points on the test. One example is “Only faculty and staff are allowed in the lounge.” I was incorrect in labeling faculty and staff as sufficient (a) and the lounge as necessary (b). The answer in the book was “If in lounge==>faculty and staff”. Please help!

    • Hi Joy,

      “Only” always introduces the necessary condition. That’s a rule you can take to the bank. So, the answer in the book was correct. One thing to watch out for, “the only” always introduces the sufficient condition. So, in this case, you could say the exact same thing by saying, “The only people allowed in the lounge are faculty and staff.”

      I’d recommend making flashcards with the rule governing the situation (in this case, “Only introduces the necessary condition”) and a few examples with corresponding diagrams. It’ll become second nature, but it takes practice.

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