Logical Reasoning Chapter 2

Logical Reasoning Chapter 2: Arguments and Inferences The Four Stimulus Types and Description: Argument – Premises and conclusions Premise Sets – Non – contradictory premises Paradox – Contradictory premises Debate – Two speakers Arguments: Most LSAT stimuli are arguments. These arguments are made up of premises and conclusions. Premises are facts, and conclusions are the opinions or claims based on those facts. When you put them together, you get an argument—which is the foundation of the LSAT. Premise Sets: Premise Sets are the second most common type of stimulus. They include only premises and no conclusion. They’re simply a group of facts for you to think about and connect. Paradox: Paradoxes are a special kind of Premise Set. In a Paradox, the premises seem to contradict each other, which make the stimulus confusing. Paradoxes make you wonder, “How can that be true?” Debate: Debates are stimuli where two people are speaking. One or both of them will usually make an argument. They discuss or argue about whether a specific point is true or false. The CLIR: When you’re doing an LR section, you will always detect the stimulus type and perform an analytical task associated with that stimulus type; these tasks are collectively called the CLIR (pronounced “CLEAR”). Debate – Controversy Argument – Loophole Premise Set – Inference Paradox – Resolution For Instance, when you see an Argument stimulus, you will immediately design a Loophole and then proceed to the question stem. Arguments: In LR, arguments are the single most important concept you need to understand on an in – depth level. Arguments are quite simple at their core. An Argument is made up of two things: premises and conclusions. Arguments are all about the relationship between the conclusion and its premises..

Premises: Premises are the base of the argument that are used to support the conclusion. They are the facts and evidence, and cannot be questioned. Premises are not dependent on the conclusion or on other premises. Premises don't need anything to support them. If you want to get a question right, don't debate the truth of the premise. Instead, focus on how the premises fit together. Premises are defined by their relationship to the conclusion. Premises are the evidence. Conclusion: Conclusions are the judgments the author makes. Conclusions are built upon the arrangement of premises. The author takes what's been given in the premises and infers something new in the conclusion. Conclusions are based on premises. They rely on the premises. Conclusions are the part of the argument you are allowed to question. Conclusions are not necessarily ironclad; the premises are usually not arranged well enough to prove the conclusion. They are dependent on premises. If the premises aren't arranged well enough, the conclusion won't work. Conclusions are the claims. The premises are like a rope bridge, and the conclusion is like the destination on the other side. If the premises aren’t strong you can’t cross over to the conclusion. Memorize and be on the lookout for premise and conclusion indicators. Use them to guide yourself through stimuli. When indicator words are present, they are a reliable way to identify parts of an argument. However, indicator words won’t always be there to show which part of the stimulus each statement belongs to. In that case, go deeper and ask yourself about the nature of each statement: Are they facts or claims? Try to figure out which parts are the premises and which is the conclusion, based on how they interact with each other. Valid Conclusions: These are conclusions that are strongly supported. A valid conclusion must be true if the premises are true. Since we always assume the premises are true, a valid conclusion is one that must be true. It doesn't go beyond what the premises support. You must be able to prove a valid conclusion using only the information given. To come up with a valid conclusion, look for a common term between two premises and see if anything is repeated that helps you connect them. A slightly more complex valid conclusion happens when there aren't exact repeated words, but instead something that belongs to the same category in both premises. Another type of valid conclusion includes one premise talking about something that doesn't fit in a particular category, and another premise referring to something that is included in that category. They share a common element. A valid conclusion can also be called an inference, depending on the context. Valid Conclusion vs. Inferences: Valid conclusions are always presented as part of the stimulus. Inferences, on the other hand, are not part of the stimulus. An inference is something we come up with ourselves from a premise. It is a connection we make, based on that premise..

Invalid conclusions: On the LSAT, most conclusions are invalid. Invalid conclusions make the wrong connection between the premises and the conclusion. To disprove invalid conclusions, you have to object them. You need to design very strong objections that point out a specific scenario where the premises are true but the conclusion fails. These strong objections are called “Loopholes”. Valid conclusions aren’t vulnerable to reasonable loopholes, invalid conclusions are. Loopholes: To invalidate a conclusion, use these Loophole tips: 1. Always assume something is being left out of what the author chooses to present. What the stimulus doesn’t say is often more important than what it does say. 2. Don’t assume that what’s true for one group means the opposite is true for another group. Just because something applies to one side doesn’t mean the reverse applies to the other. 3. You are not allowed to fill in the gaps between the premises for the author. 4. Premises must prove the conclusion. You can’t use outside knowledge or assumptions to help the argument. 5. The LSAT often tries to fool you by mixing up two different ideas. Just because two ideas sound similar doesn't mean they are the same. Valid conclusions are proven by their premises. Invalid conclusions aren't proven by their premises. All the invalid conclusions take something for granted. Loopholes are how we attack invalid conclusions. When a word or idea is in both premises, you can usually link them to form a new idea. That new idea is what the two premises meant, but didn’t clearly say. This works in both simple and hard language—hard language just hides the link. That shared idea lets you bridge the two premises. Example (Simple Language): 1. Premise: All dogs are animals. 2. Premise: All animals need oxygen. Shared idea: “Animals” New conclusion: All dogs need oxygen. → That conclusion wasn’t stated, but it must be true based on the link. It makes an Inference based on premises. It doesn’t go against the premises but instead connects them. Complex Arguments: Intermediate Conclusion: It fulfills the argumentative role of both a premise and a conclusion. It both supports the arguments main conclusion, and is supported by its premises. Intermediate conclusion is a conclusion acting like a premise. The intermediate conclusion also needs support because it is a claim just like the main conclusion. The only difference between intermediate.

conclusion and main conclusion, in that the former supports the later. The main conclusion is proven with the help of the intermediate conclusion. Intermediate, conclusions are also known as subsidiary conclusions or sub-conclusions. If a stimulus contains two conclusion indicators, that's a huge giveaway that it has an intermediate conclusion. To tell the difference between an intermediate conclusion and a main conclusion, look for which statement relies on the other one. The intermediate conclusion supports the main conclusion, and nothing else. If there are no conclusion indicators, then simply interrogate the statements. Ask the season behind each statement; ask if they is any evidence in the stimulus, to back that statement. If you have no better answer than “reasons that aren’t mentioned” for why something is true, it’s a premise. If you have evidence for why it’s true, it’s some kind of a conclusion. If something has both evidence for why it’s true and is evidence itself, it’s an intermediate conclusion. Nested Claims and Hybrid Arguments: (i) Nested Claims: Nested Claims: When someone besides the author makes a claim, it is called a nested claim. E.g. – “Dr. Hamilton’s study found…”, “Filipe believes that..” Nested claims always look like this; they're a description of how someone believes something. If the author concludes anything themselves, they will use the nested claim as a premise for their conclusion. In that case, treat the nested clam as a premise and critique the author’s conclusion. It's important to recognize hybrid arguments because you always want to pay attention to the most important claim in the stimulus. This will help you predict the correct answer to many LR questions. (ii) Hybrid Arguments: When the stimulus is only premises and a nested claim (no author's conclusion), we call the stimulus a hybrid argument and critique the nested claim. When the author doesn't supply their own conclusion, the nested claim acts as the conclusion of the hybrid argument. In this case, you question the validity of the nested claim just like a normal conclusion. A hybrid argument is just nested claim with a few premises attached. If the author concludes anything on the own, the nested claim does not create a hybrid argument. Nested Claim in a Regular Argument  Author gives their own conclusion  Other person’s claim = Premise  You critique: The author's conclusion Hybrid Argument  Author gives NO conclusion of their own  Other person’s claim = Conclusion.

 Other statements = Premises  You critique: The nested claim (as if it were the main conclusion) How to Attack an Argument: Throughout your LR training, you will try to destroy all the conclusions you encounter by designing Loopholes. To build this skill set, always ask yourself why the conclusion is supposed to be true. Think through the possibilities that cast doubt on the way the premises (supposedly) add up to lead to the conclusion. Do this every single time you read a conclusion on the LSAT and hear someone make a questionable claims in real life. Attack the premises' relationship to one another and to the conclusion, but never question the truth of the premises. The premises are factually true, no matter how outlandish they sound or how much you may disagree with them. Always assume there is something being left out of what the author chooses to present to you. Never attack the truth of the premises; attack what the premises purposefully aren't telling you..