1 00:00:19,799 --> 00:00:25,579 If I had a nickel for every student who lost four raw points on Logical Reasoning 2 00:00:26,039 --> 00:00:32,380 strictly because of the word unless, I, uh, I would be retired on a beach somewhere. 3 00:00:33,159 --> 00:00:38,340 It is, it's easily the most expensive word on the test. 4 00:00:40,269 --> 00:00:41,929 Four raw points. 5 00:00:41,990 --> 00:00:45,769 That is literally the difference between a one sixty eight and a one seventy two. 6 00:00:46,527 --> 00:00:47,547 It really is. 7 00:00:48,007 --> 00:00:49,767 And it's not just unless. 8 00:00:50,247 --> 00:00:53,547 It's the whole cluster of four exception indicators. 9 00:00:54,087 --> 00:00:58,147 You have unless, except, until, and without. 10 00:00:59,027 --> 00:01:03,607 Standard conversational English tricks your brain into negating the wrong side of 11 00:01:03,628 --> 00:01:06,267 the conditional arrow every single time. 12 00:01:06,962 --> 00:01:12,083 Right, because in real life, when someone says you can't eat dessert unless you 13 00:01:12,102 --> 00:01:15,742 finish your vegetables, you assume those two things are just swapped around 14 00:01:15,803 --> 00:01:16,362 casually. 15 00:01:16,982 --> 00:01:22,402 But on the LSAT, that casual translation gets you wrecked on necessary assumption 16 00:01:22,442 --> 00:01:22,923 questions. 17 00:01:23,549 --> 00:01:24,409 Precisely. 18 00:01:25,149 --> 00:01:30,489 So we throw out intuition and we use what we call the Unless Equation. 19 00:01:31,389 --> 00:01:33,849 It is a two step mechanical rule. 20 00:01:34,630 --> 00:01:41,149 Step one: whatever word or idea unless modifies becomes necessary. 21 00:01:41,909 --> 00:01:46,549 That means it goes at the tail end of the arrow, after the conditional split. 22 00:01:47,192 --> 00:01:52,872 Okay, whatever word or idea unless modifies becomes necessary. 23 00:01:53,352 --> 00:01:53,672 Got it. 24 00:01:54,252 --> 00:01:58,753 So if the sentence is, no contract is binding unless signed, 25 00:01:59,312 --> 00:02:02,793 the word unless is directly modifying signed. 26 00:02:03,486 --> 00:02:04,086 Exact. 27 00:02:04,626 --> 00:02:07,186 So signed is your necessary condition. 28 00:02:07,567 --> 00:02:09,346 It goes on the right side of the arrow. 29 00:02:10,147 --> 00:02:14,087 Step two is where people hesitate: you take the remaining clause, 30 00:02:14,346 --> 00:02:19,007 which is no contract is binding, and you negate it completely to make it the 31 00:02:19,106 --> 00:02:20,906 sufficient condition on the left. 32 00:02:21,731 --> 00:02:28,232 So the negation of no contract is binding becomes the contract is binding. 33 00:02:28,923 --> 00:02:29,422 Correct. 34 00:02:30,022 --> 00:02:34,422 So your diagram is simply: Binding requires Signed. 35 00:02:35,102 --> 00:02:38,003 Or, Binding arrow Signed. 36 00:02:38,629 --> 00:02:40,389 Which makes total sense! 37 00:02:40,929 --> 00:02:45,869 But, man, when I was starting out, I remember getting totally bogged down in double 38 00:02:45,949 --> 00:02:47,969 negation traps on timed drills. 39 00:02:48,569 --> 00:02:53,149 I would see a statement like that, panic for five seconds, and draw a mistaken 40 00:02:53,210 --> 00:02:58,529 reversal like Signed arrow Binding, which is, obviously wrong. 41 00:02:59,029 --> 00:03:02,949 Just signing something doesn't automatically make it a valid contract! 42 00:03:04,549 --> 00:03:09,250 Right, you could sign a napkin with crayon, doesn't make it enforceable. 43 00:03:10,349 --> 00:03:14,449 The sanity check under pressure is always the contrapositive. 44 00:03:15,229 --> 00:03:21,649 Take your diagram, Binding arrow Signed, flip both sides, and negate them both. 45 00:03:22,489 --> 00:03:22,989 What do you get? 46 00:03:23,774 --> 00:03:27,234 Not Signed arrow Not Binding. 47 00:03:27,934 --> 00:03:31,094 If it is not signed, then it is definitely not binding. 48 00:03:31,857 --> 00:03:32,837 Five seconds. 49 00:03:33,817 --> 00:03:38,958 That contrapositive check completely eliminates the temptation to draw a mistaken 50 00:03:39,057 --> 00:03:41,177 reversal when the clock is ticking down. 51 00:03:41,882 --> 00:03:48,002 Okay, but Adrian, what happens when LSAC decides to be extra cruel and throw a 52 00:03:48,101 --> 00:03:49,581 compound clause into the mix? 53 00:03:50,121 --> 00:03:53,861 Like when they drop an or inside the unless statement? 54 00:03:54,427 --> 00:03:57,367 Ah, compound exception clauses. 55 00:03:58,047 --> 00:04:03,148 This is LSAC's favorite trap for students who rely on rote memory without 56 00:04:03,187 --> 00:04:05,068 understanding the underlying logic. 57 00:04:05,967 --> 00:04:08,507 Let's take a concrete argument. 58 00:04:08,607 --> 00:04:15,107 Suppose the stimulus says: The proposal will pass unless Director Vance dissents or 59 00:04:15,147 --> 00:04:17,048 Representative Ruiz abstains. 60 00:04:18,377 --> 00:04:21,458 Director Vance and Representative Ruiz. 61 00:04:22,077 --> 00:04:23,557 Classic board meeting drama. 62 00:04:24,337 --> 00:04:27,237 Okay, walk me through the translation step by step. 63 00:04:27,905 --> 00:04:30,924 Alright, apply step one of our equation. 64 00:04:31,664 --> 00:04:34,284 What is modified by unless? 65 00:04:34,902 --> 00:04:41,222 The entire phrase: Director Vance dissents or Representative Ruiz abstains. 66 00:04:41,702 --> 00:04:46,282 So that whole chunk goes to the right side of the arrow as the necessary condition. 67 00:04:46,966 --> 00:04:47,366 Right. 68 00:04:48,167 --> 00:04:53,566 Now step two: negate the remaining clause, proposal will pass, 69 00:04:54,086 --> 00:04:57,606 to get proposal does not pass on the left side. 70 00:04:58,467 --> 00:05:05,286 So your initial setup is: Not Pass arrow Vance Dissents OR Ruiz 71 00:05:05,366 --> 00:05:05,966 Abstains. 72 00:05:06,715 --> 00:05:07,974 Okay, clear enough. 73 00:05:08,514 --> 00:05:12,694 But the real nightmare is when you need to take the contrapositive of that compound 74 00:05:12,774 --> 00:05:15,755 statement to answer a sufficient assumption question. 75 00:05:16,319 --> 00:05:19,079 And that is where De Morgan's Law comes in. 76 00:05:19,919 --> 00:05:24,880 When you negate a compound condition containing or, or containing and, 77 00:05:25,479 --> 00:05:27,719 you have to flip the logical operator. 78 00:05:28,519 --> 00:05:34,420 This is the golden rule: and becomes or and or becomes and. 79 00:05:35,329 --> 00:05:35,850 Yes! 80 00:05:36,149 --> 00:05:39,130 That was my huge lightbulb moment when I was studying! 81 00:05:39,730 --> 00:05:43,170 And becomes or and or becomes and! 82 00:05:43,670 --> 00:05:50,549 So if you negate Vance Dissents OR Ruiz Abstains, it becomes Vance does NOT dissent 83 00:05:50,670 --> 00:05:52,949 AND Ruiz does NOT abstain! 84 00:05:53,689 --> 00:05:54,669 Beautifully done. 85 00:05:55,549 --> 00:06:02,069 So the contrapositive reads: If Vance does not dissent AND Ruiz does not 86 00:06:02,109 --> 00:06:05,130 abstain, then the proposal WILL pass. 87 00:06:05,923 --> 00:06:08,722 That feels so clean when you break it down like that. 88 00:06:09,382 --> 00:06:14,022 But, um, how do you keep from scrambling the logic when you have like fifteen 89 00:06:14,142 --> 00:06:15,882 seconds left on question twenty two? 90 00:06:16,649 --> 00:06:22,069 We use what I call the Rule of Three Flips for compound conditions. 91 00:06:22,929 --> 00:06:28,729 When taking the contrapositive of a compound statement, you do three distinct flips 92 00:06:28,789 --> 00:06:29,809 in your mental audit. 93 00:06:30,849 --> 00:06:34,750 One: flip the order of the terms from right to left. 94 00:06:35,729 --> 00:06:39,649 Two: flip the negations on every individual term. 95 00:06:40,609 --> 00:06:46,269 Three: flip the boolean operator itself, so or flips to and. 96 00:06:47,084 --> 00:06:48,324 Three flips. 97 00:06:48,884 --> 00:06:52,585 Flip terms, flip negations, flip operators. 98 00:06:53,224 --> 00:06:57,844 That ten second mental checklist saved my score so many times on section four. 99 00:06:59,407 --> 00:07:01,486 It works every single time. 100 00:07:02,226 --> 00:07:08,026 Master the three flips, and exception clauses go from being a trap to being free 101 00:07:08,186 --> 00:07:08,627 points. 102 00:07:09,298 --> 00:07:11,877 Free points are my favorite kind of points. 103 00:07:12,617 --> 00:07:14,017 Alright, good chatting, Adrian. 104 00:07:14,655 --> 00:07:15,615 Talk soon, Nora.