Discussion: Argument Analysis

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Discussion: Argument Analysis

Number of replies: 35

Try to formulate examples of three important patterns of argument: modus ponens, modus tollens, and reductio. Then, for this argument sent to a newspaper by a reader responding to an article claiming that Shakespeare was Italian, identify the argument's main conclusion and spell out the argument's premises. 

"So Shakespeare was an Italian, because almost half of his plays are set in Italy. Almost all of Isaac Asimov's novels are set in outer space – does that mean he was a Martian?" – Graham Simpson

Share your thoughts on the discussion forum. Make sure to review and respond to other students' posts, as well.

In reply to First post

Re: Discussion: Argument Analysis

by Colte Rindlesbach -
Modus Ponens:
All thumbs are fingers, bill has two thumbs. who has at least two fingers? that guyyyy (bill)

Modus tollens:
if Beth stole 100K then there would be at least 100K in her off shore bank account. There is not at least 100K in her off shore bank account. therefore, she couldn't have stolen the money

Reductio:
If we could obtain world peace through only telling the truth all the time, all people would have times where they would need to say hard truths. hard truths have been known to hurt people. Hurting people is not peaceful. therefore, the solution to world peace cannot be telling the truth all the time.

Shakespeare argument
P1) shakespeare was from italy
P1 a.) Almost half of his plays were set in italy.
P2) Almost all of Asimovs books were set in space.
C) therefore, Isaac Asinov Must be from space
( If the majority of a writers work takes place in a specific setting then they must have grown up/raised/from that place.) 
In reply to Colte Rindlesbach

Re: Discussion: Argument Analysis

by John Heathcliff -
Hi Colte,

I liked your Reductio example because its such a common misconception and used to rationalize not telling the truth or doing the hard work to find a nice way to tell a hard truth.

I am not sure the conclusion you show if the right one because Graham Simpson poses it as a question.
In reply to First post

Re: Discussion: Argument Analysis

by Catherine Quinn -
Modus Ponens:
If I wash my hair, my hair will be wet. I am washing my hair. Therefore, my hair is wet.

Modus Tollens:
If the fire alarm goes off, then there is a fire. There is no fire. Therefore, the fire alarm did not go off.

Assumption: All cats are black.
Reductio: If all cats are black, and we encounter a white cat, it contradicts the initial assumption that all cats must be black. Therefore, the assumption that all cats are black leads to an absurdity.

Conclusion: Shakespeare was not Italian.

Premisses:
- Almost half of Shakespeare's plays are set in Italy.
- Drawing an analogy, Graham presents the case of Isaac Asimov, noting that almost all of Asimov's novels are set in outer space.
- The analogy questions the validity of the claim that setting works in a particular location implies the origin of the creator, suggesting that if we follow this logic, Isaac Asimov would be considered a Martian.
In reply to First post

Re: Discussion: Argument Analysis

by Desiree Polo -
Types of Argumentation:
1. Modus Ponens:
If P, then Q.
P is accurate.
Q is therefore true.
For instance, the grass becomes wet when it rains. It's pouring with rain. The grass is damp as a result.

2. Modus Tollens:
If P, then Q.
Q is untrue.
P is thus untrue.
Example: I'll pass the exam if I study diligently. I didn't finish the test. I did not study very hard as a result.

3. Limitation to the absurd:
Assume that the conclusion is false (not P).
Demonstrate how this results in an absurdity or contradiction.
As a result, the first conclusion (P) had to be accurate.
Example: Assume that zero (not P) cannot be used to divide an integer. One divided by zero. This results in the contradiction and nonsensical assertion 1 = 0. Consequently, zero (P) may be used to divide numbers.

Evaluating the Argument of Graham Simpson:

Primary Finding: Shakespeare was not of Italian descent.

Shakespeare wrote plays that are almost entirely set in Italy.
The majority of Isaac Asimov's books take place in space.
It was not a Martian Asimov.

Justification:
By comparison, Graham Simpson applies a type of reductio ad absurdum. He applies the same reasoning to another author (Asimov) and assumes the reverse of what the newspaper claims—that Shakespeare was Italian. Simpson demonstrates that Asimov's Martian identity is nonsensical given his space-themed literature, implying that Shakespeare and Italy do not follow the same reasoning. This leads to an absurdity, exposing the faulty logic in the first assertion.

It's crucial to remember that Simpson's example is not flawless. Fictional locales can provide details about an author's history, but they do not prove a writer's nationality. Shakespeare was not Italian, despite the fact that his reasoning successfully refutes the newspaper's assertion.
In reply to First post

Re: Discussion: Argument Analysis

by Olha Semeniuk -
here are examples of each pattern of argument:

Modus Ponens:

If it's raining (P), then the streets are wet (Q).
It's raining (P).
Therefore, the streets are wet (Q).
Modus Tollens:

If it's snowing (P), then the ground is covered in snow (Q).
The ground is not covered in snow (¬Q).
Therefore, it's not snowing (¬P).
Reductio ad Absurdum:

Suppose we want to prove that all triangles have four sides.
Assume a triangle (A) has three sides.
If we add one more side to the triangle, it now has four sides.
But that contradicts the definition of a triangle.
Therefore, our initial assumption that all triangles have four sides leads to an absurd conclusion, thus proving that all triangles do indeed have three sides.
Now, for the argument sent to the newspaper by Graham Simpson:

Main Conclusion: Shakespeare was not necessarily Italian.

Premises:

Almost half of Shakespeare's plays are set in Italy.
Setting works of fiction in a particular location does not necessarily indicate the origin of the author.
Isaac Asimov, known for his science fiction novels, frequently set his stories in outer space.
It would be illogical to conclude that Asimov was Martian simply because he set his stories in outer space.
In reply to First post

Re: Discussion: Argument Analysis

by John Heathcliff -
MP: If one drinks a full bottle of whiskey at a party, one would be legally drunk. I drank a full bottle of whiskey at a party, therefore I am legally drunk.
MT: If one drinks a full bottle of whiskey at a party, one would be legally drunk. I did not drink whiskey or any other alcohol at the party, therefore I am not legally drunk.
Reductio ad Asurdum: There are 16 shots in a bottle of whiskey. If one starts drinking whiskey in the morning and only drinks one shot of whiskey per hour one will not be as drunk as if one drinks a full bottle of whiskey at a party.

P1 If Shakespeare is an Italian because almost half his were set it Italy
P2 Then, Isaac Asimov could be a Martian since almost all of his novels are set in outer space
C Shakespeare is as likely to be an Italian as Asimov is to be a Martian.
In reply to John Heathcliff

Re: Discussion: Argument Analysis

by Gift Kabengele -
That is a very good analysis and proper understanding of the Shakespeare's analytical pedegreee
In reply to John Heathcliff

Re: Discussion: Argument Analysis

by Ryan Theobald -
Great use of a single bottle of whiskey to develop your three arguments.

I appreciate your breakdown of Shakespeare and Asimov and determining where they hail from. I took the passage or more definitive, where you used probability, well done.
In reply to First post

Re: Discussion: Argument Analysis

by Jayne Boehme -
Modus Ponens: If human, then breathing is required. Ed is human. Therefore, he must breathe.
Modus Tollens: If z is a skilled potter, then z handles clay. Z does not/has not handled clay. Therefore, z is not a skilled potter.
Reductio: Sel is a happy person. Sel has no friends or family. Therefore, Sel is not a happy person.

P1) More than half of Shakespeare's plays are set in Italy;
P2) (sub conclusion) therefore, Shakespeare was Italian.
P3) (parallel to P1) Almost all of Asimov's novels are set in outer space;
Conclusion (parallel to P2): therefore, Asimov is a Martian/from outer space?
In reply to First post

Re: Discussion: Argument Analysis

by asifa shaikh -
Modus Ponens:
If I wash my hair, my hair will be wet. I am washing my hair. Therefore, my hair is wet.

Modus Tollens:
If the fire alarm goes off, then there is a fire. There is no fire. Therefore, the fire alarm did not go off. 

Assumption: All cats are black.
Reductio: If all cats are black, and we encounter a white cat, it contradicts the initial assumption that all cats must be black. Therefore, the assumption that all cats are black leads to an absurdity. 

Conclusion: Shakespeare was not Italian.

Premisses:
- Almost half of Shakespeare's plays are set in Italy.
- Drawing an analogy, Graham presents the case of Isaac Asimov, noting that almost all of Asimov's novels are set in outer space.
- The analogy questions the validity of the claim that setting works in a particular location implies the origin of the creator, suggesting that if we follow this logic, Isaac Asimov would be considered a Martian

In reply to First post

Re: Discussion: Argument Analysis

by Rehan Ullah -
Examples of the three important patterns of argument:

1. Modus Ponens:
If A, then B.
A.
Therefore, B.
Example: If it is raining, then the ground will be wet. It is raining. Therefore, the ground is wet.

2. Modus Tollens:
If A, then B.
Not B.
Therefore, not A.
Example: If it is raining, then the ground will be wet. The ground is not wet. Therefore, it is not raining.

3. Reductio ad Absurdum:
Assume A.
Deduce a contradiction.
Conclude that the assumption is false.
Example: Assume that all cats can fly. If all cats can fly, then they should be able to fly to the moon. This leads to a contradiction, as it is not possible for cats to fly to the moon. Therefore, the assumption that all cats can fly is false.

Now, for the argument sent to the newspaper by the reader:

Main Conclusion: Shakespeare was not necessarily Italian.

Premises:
1. Almost half of Shakespeare's plays are set in Italy.
2. Isaac Asimov's novels are mostly set in outer space.
3. Asimov being associated with outer space doesn't make him a Martian.

In this argument, the reader is using a form of reductio ad absurdum to challenge the claim that Shakespeare was Italian. By comparing Shakespeare's plays being set in Italy to Asimov's novels being set in outer space, the reader highlights the absurdity of concluding Shakespeare's nationality based solely on the setting of his works. Thus, the main conclusion is that Shakespeare's works' settings do not determine his nationality, and the premises support this by showing the fallacy in making such an inference.
In reply to First post

Re: Discussion: Argument Analysis

by Erin Berger -
Modus ponens: If the sun is shining then the ground is warm. The sun is shining. Therefore, the ground is warm.
Modus tollens: If the car is on then the keys are in the ignition. There are no keys in the ignition. Therefore, the car is not on.
Reductio: 'Money buys happiness' is an absurd statement as money can be used to fund lots of activities that lead to sadness and destruction.

The main conclusion to the argument is that where your plays are set, that means the creator is from that location.
In reply to First post

Re: Discussion: Argument Analysis

by Beato Candundu -
Modus ponens
Everyday it rains in the city. When it rains it gets slippery. Today it rained therefore it is slippery.

Modis Tollens
Marcus killed his girlfriend. At the alleged time of the killing Marcus was giving a lecture in Taipri. Therefore Marcus could not have killed his girlfriend.

Reductio
Forest fire arson setting is said to help clear the forest. Fire arson is known to destroy the wilderness habitat. Forest fire is illegal in most of the countries. Therefore, fire settings does not do good to the ecosystem.
In reply to First post

Re: Discussion: Argument Analysis

by Daniel Sosa -
If your mom lives in New York City, she lives in the U.S. Your mom lives in New York City. Therefore, she lives in the U.S.
If your mom lives in New York City, she lives in the U.S. Your mom does not like in the U.S. Therefore, your mom does not live in New York City.

An interesting topic. If they are referring to ethnicity, there is a chance of countering Graham's argument. But if they are referring to race, he might have a valid argument.
In reply to First post

Re: Discussion: Argument Analysis

by Ahmed Abdirahman Ahmed -
Greetings to all classmates,

Modus ponens is a valid argument form that follows the principle of affirming the antecedent. It can be summarized as follows: if we have a conditional statement "If P, then Q" as the first premise, and we know that P is true as the second premise, then we can logically conclude that Q must also be true as the conclusion (PhilosophyALevel.com, 2023). 

On the other hand, modus tollens is a valid argument form that operates by denying the consequent (PhilosophyALevel.com, 2023). It can be summarized as follows: if we have a conditional statement "If P, then Q" as the first premise, and we know that Q is not true as the second premise, then we can logically conclude that P must also not be true as the conclusion. 

In contrast to modus ponens and modus tollens, reductio ad absurdum is an argument form that aims to disprove a claim by showing that assuming its truth leads to an absurd or contradictory conclusion. It involves assuming the opposite of what is being argued and then demonstrating that it leads to an absurd or contradictory result. By showing the absurdity of the assumed position, we can refute the original claim. 

Modus ponens example: 
Premise 1: If a camel has milk, then it can be milked. 
Premise 2: The camel has milk. 
Conclusion: Therefore, the camel can be milked. 

 

Modus Tollens examples:  
Premise 1: If a country experiences a civil war, then there is significant internal conflict.
Premise 2: There is no significant internal conflict. 

Conclusion: Therefore, the country is not experiencing a civil war. 


Claim: It is possible to use the net (computer network) without the internet. 
 Assumption: It is not possible to use the net without the internet. 

 If it were not possible to use the net without the internet, it would mean that local computer networks, such as LANs, could not function independently. However, LANs are widely used for internal communication and file sharing, contradicting the assumption. Therefore, the claim that it is possible to use the net without the internet holds true, as the assumption leads to an absurdity. 

Main Conclusion: Shakespeare was not necessarily Italian. 
Premises: 
Almost half of Shakespeare's plays are set in Italy. 

Isaac Asimov's novels are set in outer space, but that doesn't mean he was a Martian. 


Obviously, Shakespeare was an English poet. According to Biography.Com Editors and Donica (2023), William Shakespeare, a renowned English poet, playwright, and actor of the Renaissance era, played a significant role as a member of the King's Men theatrical company starting around 1594. Shakespeare's literary contributions, including a minimum of 37 plays, 154 sonnets, and 2 narrative poems, have gained worldwide recognition for their profound exploration of human emotions, conflicts, and have continued to be celebrated for over four centuries. 

 

References: Biography.Com Editors., & Donica, A. (2023, April 21). William Shakespeare. https://www.biography.com/authors-writers/william-shakespeare 

PhilosophyALevel.com. (2023, May 28). If P then Q: Modus Ponens, Modus Tollens, Affirming the Consequent, and Denying the Antecedent. https://philosophyalevel.com/posts/if-p-then-q-modus-ponens-modus-tollens/ 

 


In reply to First post

Re: Discussion: Argument Analysis

by Cris Hass -
Modus ponens
If I go to the beach, I will get tan. I went to the beach. Therefore I am tan.

Modus tollens
If I get arrested, I broke the law. I didn't break the law, so I didn't get arrested

Reductio
Joe fell off the top of a building, so Joe must have died.
Not necessarily, if firefighters were at the bottom ready to catch him he could have survived.

Shakespeare argument
P1) Almost half of Shakespeare's plays are set in Italy
P2) Almost all of Isaac Asimov's novels are set in outer space
C) Shakespeare is just as likely to be Italian as Isaac Asimov is to be a Martian
In reply to First post

Re: Discussion: Argument Analysis

by Sanika Bari -
Types of Argumentation:
1. Modus Ponens:
If P, then Q.
P is accurate.
Q is therefore true.
For instance, the grass becomes wet when it rains. It's pouring with rain. The grass is damp as a result.

2. Modus Tollens:
If P, then Q.
Q is untrue.
P is thus untrue.
Example: I'll pass the exam if I study diligently. I didn't finish the test. I did not study very hard as a result.

3. Limitation to the absurd:
Assume that the conclusion is false (not P).
Demonstrate how this results in an absurdity or contradiction.
As a result, the first conclusion (P) had to be accurate.
Example: Assume that zero (not P) cannot be used to divide an integer. One divided by zero. This results in the contradiction and nonsensical assertion 1 = 0. Consequently, zero (P) may be used to divide numbers.

Evaluating the Argument of Graham Simpson:

Primary Finding: Shakespeare was not of Italian descent.

Shakespeare wrote plays that are almost entirely set in Italy.
The majority of Isaac Asimov's books take place in space.
It was not a Martian Asimov.

Justification:
By comparison, Graham Simpson applies a type of reductio ad absurdum. He applies the same reasoning to another author (Asimov) and assumes the reverse of what the newspaper claims—that Shakespeare was Italian. Simpson demonstrates that Asimov's Martian identity is nonsensical given his space-themed literature, implying that Shakespeare and Italy do not follow the same reasoning. This leads to an absurdity, exposing the faulty logic in the first assertion.

It's crucial to remember that Simpson's example is not flawless. Fictional locales can provide details about an author's history, but they do not prove a writer's nationality. Shakespeare was not Italian, despite the fact that his reasoning successfully refutes the newspaper's assertion.
In reply to Sanika Bari

Re: Discussion: Argument Analysis

by Shaqoria Hay -
Oh I like how you used math as your Reductio that was a great idea. I feel like we often believe since a person spends most of their time in a particular place or they always speak about places in such high standard that an individual may be from there or they may love that place. Like you said we have to remember that fictional locales can provide detail, but does not tell a persons nationality. I feel we have to be careful and make sure we are paying attention to certain key words because it does give hints that this is not something true.
In reply to First post

Re: Discussion: Argument Analysis

by diana kydd -
Premises:

Almost half of Shakespeare's plays are set in Italy.
Isaac Asimov's novels are mostly set in outer space.
If setting plays or novels in a particular location implies the origin of the writer, then Isaac Asimov would be considered a Martian.
It is absurd to conclude that Isaac Asimov is a Martian based solely on the setting of his novels.
Argument structure:

Premise: Almost half of Shakespeare's plays are set in Italy.
Premise: Isaac Asimov's novels are mostly set in outer space.
Premise: If setting plays or novels in a particular location implies the origin of the writer, then Isaac Asimov would be considered a Martian.
Premise: It is absurd to conclude that Isaac Asimov is a Martian based solely on the setting of his novels.
Conclusion: Therefore, Shakespeare was not necessarily Italian.
In reply to First post

Re: Discussion: Argument Analysis

by Michael Starnes -
Modus Ponens:
Example: If it's raining, then the streets will be wet. It's raining. Therefore, the streets are wet.
Modus Tollens:
Example: If it's raining, then the streets will be wet. The streets are not wet. Therefore, it's not raining.
Reductio ad Absurdum:
Example: If everyone drove a pink car, traffic accidents would decrease. That's absurd, so not everyone should drive a pink car.
Now, let's analyze the argument sent to the newspaper by Graham Simpson:

Main Conclusion: Shakespeare was not necessarily Italian.

Premises:

Almost half of Shakespeare's plays are set in Italy. Setting a significant number of works in a particular location does not necessarily imply the creator's nationality or origin. An analogy is drawn with Isaac Asimov, whose novels are predominantly set in outer space, but that doesn't imply he was a Martian.
So, Simpson's argument suggests that just because a significant portion of Shakespeare's plays are set in Italy, it doesn't logically follow that he must have been Italian. He uses the analogy with Isaac Asimov to illustrate that an author's choice of setting does not determine their nationality or origin. Therefore, Simpson refutes the claim that Shakespeare was Italian based solely on the setting of his plays.
In reply to First post

Re: Discussion: Argument Analysis

by monica thompson -
Modus Ponens
If its snowing outside then it must be cold. It is snowing, therefore it is cold.

Modus Tollens
If its snowing outside then it must be cold. It is not cold, therefore it is not snowing.

Reductio
Kids should always be happy. Brushing teeth makes kids unhappy so should shouldn't be forced. Not brushing teeth causes pain and tooth rot. Pain makes kids unhappy.

1 - Almost half of Shakespeare's plays are set it Italy
2 - Shakespeare was an Italian (from 1)
3 - Almost all of Asimov's novels are set in outer space
4 - Asimov was a Martian (from 1-2, 3)
In reply to First post

Re: Discussion: Argument Analysis

by JOSAFAT VANDULF ELANO -
Simpson uses a form of reductio ad absurdum by showing that if we apply the same logic to Asimov, we would conclude he's a Martian, which is clearly absurd. Therefore, he implies that the argument claiming Shakespeare was Italian based on play settings alone is flawed.
In reply to JOSAFAT VANDULF ELANO

Re: Discussion: Argument Analysis

by Shaqoria Hay -
You gave us the second part in basic logic. I feel like when we say certain things we do not often pay attention to the key words being used. Because we all know that Shakespeare based to give you an Italian feeling but it does not mean that his nationality has to be Italian or he has to be from Italy. And your right coming to and assumption that some is a Martin based of the scenery of how something looks is absurd.
In reply to First post

Re: Discussion: Argument Analysis

by JOSAFAT VANDULF ELANO -
Simpson uses a form of reductio ad absurdum by showing that if we apply the same logic to Asimov, we would conclude he's a Martian, which is clearly absurd. Therefore, he implies that the argument claiming Shakespeare was Italian based on play settings alone is flawed.
In reply to First post

Re: Discussion: Argument Analysis

by WLLM12 G -
Example: If it's raining, then the ground is wet. It's raining. Therefore, the ground is wet.
Modus Tollens:

Example: If it's raining, then the ground is wet. The ground is not wet. Therefore, it's not raining.
Reductio ad Absurdum:

Example: If cats can fly, then they have wings. Cats don't have wings. Therefore, cats can't fly.
Argument on Shakespeare's Nationality:

Conclusion: Shakespeare was not necessarily Italian.
Premises:
Almost half of Shakespeare's plays are set in Italy.
Isaac Asimov's novels are mostly set in outer space.
It doesn't mean Asimov is Martian.
In Graham Simpson's argument, the main conclusion is that just because Shakespeare's plays are often set in Italy, it doesn't necessarily mean he was Italian. This is supported by the comparison to Isaac Asimov's novels, which are predominantly set in outer space, yet he is not assumed to be Martian.
In reply to First post

Re: Discussion: Argument Analysis

by Valentin Ionescu -
Modus ponens: If you are good, you'll go to heaven. You are good. So you'll go to heaven.
Modus tollens: If I like the joke, then I laugh. I'm not laughing, therefore I don't like the joke.
Reductio: Gravity exist. If not, we would float into space.
In reply to First post

Re: Discussion: Argument Analysis

by Ryan Theobald -
Modus Ponens – If the clouds are dark it will rain. The clouds are dark; therefore it will rain.
Modus Tollens – If Kyle is working then he has an income. Kyle does not have an income; therefore, he is not working.
Reductio – Someone argues that video games require a television to play. The assumption is a TV is the only way to visually display a video game. Reductio ad absurdum can be used to counter the argument saying that a laptop can be used to play video games. This disproves the original argument. Therefore their argument is invalid.

Main Conclusion – Shakespeare was an Italian.
Premise – half of his plays are set in Italy
Premise through analogy – Isaac Asimov writes about outer space which means he is a martin.
The analogy leads the reader to believe that the authors must come from where they stage the bulk of their work.
In reply to First post

Re: Discussion: Argument Analysis

by Luis Vargas -
Assumptions do not make good on argumentative analysis
In reply to First post

Re: Discussion: Argument Analysis

by Shaqoria Hay -
Modus ponens- Knees are apart of the body. Jenny has two knees. Who has two knees?
Modus tollens- It is raining. Then ground is wet. The ground is not wet. Therefore, it is not raining.
Reductio- All rainbows have a portal. Then we should be able to access the portal. This leads to a contradiction it is not possible to access portal through rainbows.

P1-States Shakespeare is Italian because his plays were mostly in Italy.
p2-States Asimov's because his novel are based in outer space he was a Martin.
C- Just because an induvial base something off a particular area doesn't mean that it is true. That induvial may prefer that setting or environment it may help them get great ideas or it could be their peaceful place to work.
In reply to First post

Re: Discussion: Argument Analysis

by Leslie Tapper -
Modus ponens: If the number 2 is even. And even numbers are divisible by 2 without leaving a remainder. Then the number 2 will always be an even number.
Modus tollens: It's sunny so it's warm. It is not warm today. So it is not sunny.
Reductio: All short people are always angry, but most short people are kind unless provoked and the definition of 'short' can vary from person to person. So every short person isn't always angry.

Shakespeare:
P1. Shakespeare was Italian because almost half his plays are set in Italy.
P2. Issac's novels are set in outer space so he was a martian.
Conclusion: Shakespeare was italian because of the location of majority of his plays. (an absurd counterarg?)
In reply to First post

Re: Discussion: Argument Analysis

by Siddika Koly -

1. Modus Ponens: If I had a car, I would have gone there, I don't have a car, so I didn't go.


2. Modus tollens: If there was Karim, Rahim would have done well. Rahim didn't do well, Karim wasn't there 


3. I have a flying car, therefore I can fly


Argument analysis: 

Conclusion: Shakespeare isn't Italian

Premises:

1. Isaac Asimov wrote books on space

2. But He isn't from space

3. Shakespeare wrote on Italy.


In reply to First post

Re: Discussion: Argument Analysis

by Melissa Aves -
Shakespeare's plays were all set in Italy.
Most of Asimov's plays were set in outer space.
Shakespeare is Italian and Asimov is from outer space.
In reply to First post

Re: Discussion: Argument Analysis

by Aedan Masker -
Modus ponens: IF P then Q. P therefore Q
The dog will not go outside if it is raining. It is raining, therefore the dog will not go outside.

Modus tollens: If P then Q. Not Q, therefore not P.
The dog will not go outside if it is raining. The dog is outside, therefore it is not raining.

Reductio:
The Earth is flat. Flat surfaces have edges, so people must be falling off the edge of the Earth. No one has ever fallen over the edge of the Earth, so the Earth cannot be flat.



Shakespeare:
Reductio argument is being given.
P1: Writers set their works more often in the place they are from
P2: Shakespeare set almost half of his plays in Italy.
C1 (intermediate): Shakespeare is Italian.

Graham goes on to reduce this argument to absurd by
assuming P1) is true.
Gives his own P2) Almost all of Isaac Asimov's novels are set in outer space
C) So Asimov is a Martian? - Absurd conclusion so P1 must be false
In reply to First post

Re: Discussion: Argument Analysis

by liel Mashiach -
Modus Ponens:
Example:
If it's raining, then the streets will be wet.
It's raining.
Therefore, the streets are wet.

Modus Tollens:
Example:
If it's my car, then it's in the garage.
It's not in the garage.
Therefore, it's not my car.

Reductio ad Absurdum:
Example:
If everyone jumped off a cliff, then it would be safe.
It's not safe to jump off a cliff.
Therefore, not everyone jumping off a cliff would be safe.

For the argument provided by Graham Simpson:
Main Conclusion: Shakespeare was not necessarily Italian.
Premises:

Almost half of Shakespeare's plays are set in Italy.
Isaac Asimov's novels are set in outer space.
Just because Asimov's novels are set in outer space doesn't mean he was Martian, implying that setting does not necessarily determine an author's nationality or identity.