Deductive Logic
Now that we know a bit about arguments, let’s dig deeper into their grammar, unlocking the power of analysis. After all, the LSAT’s approach to arguments is about assessing validity in arguments that have pieces missing. Let’s take advantage of what we can learn from the contents of an argument to make this more efficient.
The Claim
Subject and Predicate
Think of sentences as little stories or messages. In every story or message, there's usually someone or something that the story is about, and then there's what's happening in that story. That's where the idea of subjects and predicates come in.
What's a Subject?
The subject is the star of your sentence – the person, place, thing, or idea that's front and center. It's who or what the sentence is all about. If you're ever trying to spot the subject in a sentence, just ask yourself, "Who or what is this sentence about?" The answer you get is your subject.
Finding the Subject:
Ask "Who?" or "What?" before the verb. Your answer is often the subject.
Look for the noun or pronoun. This is usually your subject, doing something or being described.
What’s a Predicate?
The predicate is like the plot of your little sentence story. It tells you what's happening. It includes the verb – that's the action or state of being – and can also include other details that give you the full scoop on what the subject is doing or what's being done to the subject.
Finding the Predicate:
Zero in on the verb. Every predicate will have one, telling you what action is taking place or what state the subject is in.
Figure out the action or state. The predicate fills you in on what the subject's up to or what condition it's in.
Telling Them Apart
Where they hang out: The subject usually shows up before the predicate in a sentence. Though sometimes, like in questions, prescriptions, or passive voice sentences, they might switch places.
Their roles: The subject is the "who" or "what" the sentence revolves around. The predicate is the part that tells the story about the subject.
What they're made of: Subjects are typically nouns or pronouns. Predicates revolve around a verb and include other bits that build on the story.
Examples in Plain Language
"My cat sleeps."
Subject: "My cat"
(Who's the star? My cat.)
Predicate: "sleeps"
(What's the plot? Sleeping.)
"The pizza tastes amazing."
Subject: "The pizza" (What's this sentence about? The pizza.)
Predicate: "tastes amazing" (What's happening? It tastes amazing.)
Why does this matter?
Different types of premises relate to different parts of the claim!
The Subject and Minor Premises
Minor premises are facts that we know about the situation. In a valid argument, those facts are ABOUT the subject of the claim. If they weren’t, they wouldn’t be relevant; we wouldn’t care about them.
The Predicate and Major Premise
A Major premise is a rule or principle that tells us under what circumstances we can claim what we are claiming. That means that the rule must ADDRESS the predicate of the conclusion. If it didn’t, we wouldn’t be able to claim anything.
So, to help you organize your thinking, knowing what your Subject are Predicate are helps to determine which premises are Grounds for the argument and which others are the intended Warrant. Conversely, if you’re confused about what the Claim is, identifying the Grounds and Warrant can point you in the right direction.
Referential Pronouns
“This” is important!
Some claims are clear and explicit:
The pizza will be delicious or The cat must be asleep.
But sometimes, in the context of a larger argument, some information can just be referenced in the claim where it is explicit elsewhere:
I can’t find the cat anywhere. He only disappears like this when he’s sleeping, so he must be asleep.
In that example, the claim statement is He must be asleep. We of course know that we are referring to the cat, but what if the argument got more complex, say like this:
Many climate change deniers tout the adverse consequences of renewable energy production as a sufficient reason to limit its adoption. However, they are wrong to want to do so. The global adoption of renewable energy sources is not merely beneficial but essential for the future of our planet, as it addresses critical issues like climate change, energy security, and economic growth. This transition can mitigate the adverse effects of fossil fuels, promote sustainable development, and ensure a healthier environment for future generations.
Whoa. This one is dense to say the least.
The claim, in case you missed it, is However, they are wrong to do so. It will take some digging to figure out who “they” is and what “to want to do so” refers to, so once we do we should memorialize it and make it our “new” claim.
Quick Analysis: “They” is the “many climate change deniers” and “to want to do so” is “to limit its adoption”. Oh shoot, another referential pronoun! “Its adoption” refers to “the adoption of renewable energy production”
So no we fill it all in: Many climate change deniers are wrong to want to limit the adoption of renewable energy.
Often it is helpful when handling Claims to “fill in” referential pronouns like “this”, “that”, “these”, or “those” and even regular pronouns like “he”, “she”, or “they” with the people or ideas they are referring to. This can clarify your analysis to make sure your circuit is set up for success.
Negative to Affirmative
Yes, and…
So, what is our author actually saying? If that thing is wrong, what is right?
This is the essence of rebuttal to a counterargument. We need to clarify not just what we are arguing against but also what we are arguing FOR. The argument is going to go on to tell us what the author actually does believe, and those things will be in support of both denying the counterargument and affirming this new, implied argument. But the implied argument is clearer. There are fewer hoops to jump through logically. So let’s be sure we articulate it.
Taking our previous climate change argument, we had left the claim as
Many climate change deniers are wrong to want to limit the adoption of renewable energy
If the climate change deniers are wrong to want to limit it, what does the author believe is the right thing? The author must believe that we should not limit it.
A far more functional and useful claim then would be:
Renewable energy production should not be limited
In that form, we now have a Conclusion Subject of Renewable energy production, something about which we could be given plenty of evidence (Minor Premises!) and a Conclusion Predicate saying that something should not be limited, about which we can certainly imagine a rule or principle telling us.
That works!
ACTIVE vs. PASSIVE VOICE
Most sentences you will see on the LSAT will be in “Active Voice,” which means that the Subject of the verb is the one actually DOING the verb. But sometimes, the Subject and Object will “switch roles” and the new Subject will be the recipient of the verb. This is done in English by combining the verb “to be” (be, am, is, are, was, were, being, been) with the participle form of the verb.
Active Voice:
In active voice, the subject of the sentence performs the action.
Structure: Subject + Verb + Object.
Example: "The chef cooked the meal."
Passive Voice:
In passive voice, the subject of the sentence is acted upon by the verb.
Structure: Object + "to be" Verb + Past Participle + (by Subject).
Example: "The meal was cooked by the chef."
When to Use Passive Voice
While active voice is generally preferred for its clarity and directness, passive voice has its own valuable uses, especially in certain contexts. On the LSAT, recognizing conclusions for which Passive Voice is actually the right choice gives you a leg up. Here are some scenarios where passive voice might be the better choice:
Emphasizing the Action or Result:
When the action or result is more important than the subject performing the action.
Example: "A new policy was implemented to improve efficiency."
With this statement, you might not know who implemented the policy, so you couldn’t change to active voice unless that fact is present elsewhere. That aside, the facts you’re likely to get will be about the policy, so having it as your subject aligns better with that fundamental argument structure.
Unknown or Irrelevant Subject:
When the doer of the action is unknown, unimportant, or obvious from context.
Example: "The vase was broken."
Even more so than the previous example, you’re stuck here only able to analyze facts about the vase., so the vase should be your subject.
Scientific and Technical Writing:
Common in scientific papers and technical manuals where the focus is on the process or results rather than the researcher or technician.
Example: "The experiment was conducted under controlled conditions."
The scientists themselves are not important here, as what we are analyzing is the result of the experiment.
Prescriptive Statements:
To give instructions or guidelines where the emphasis is on the action that needs to be performed.
Example: "The medication should be taken with food."
Prescriptive claims (involving “should”) are a little trickier. You might think that we should rephrase this in our minds to “You should take the medication with food.” There are definitely contexts in which my justification for saying as much is something about YOU (“You have a sensitive stomach” for instance) But, other times, the evidence provided will be about the medication (“This pill is especially destructive to the stomach lining” or “This pill is particularly acidic.”) So in a prescriptive claim, pay attention to the evidence provided and adjust accordingly.
Examples in Context
Active: "The committee will review the applications."
Passive: "The applications will be reviewed by the committee."
Active: "You must fill out this form."
Passive: "This form must be filled out."
Active: "They should install the software by Friday."
Passive: "The software should be installed by Friday."
When Passive Voice may be Right
Emphasizing the Action/Result: "Vaccinations were administered to all students."
Unknown/Irrelevant Subject: "The documents were shredded."
Scientific/Technical Writing: "The samples were analyzed using chromatography."
Prescriptive Statements: "The equipment should be handled with care."
Using Passive Voice strategically in your “rephrases” of conclusions can help convey the desired emphasis and clarity, especially when the focus should be on the action or result rather than the actor.