Wednesday, January 19, 2022

Some sample arguments for review

Below are some sample arguments. (What are arguments? Check your materials). Your questions about these arguments are this: 

  • Are these arguments logically valid or not? 
  • If they are valid, what is the argument pattern
  • If they are valid, are they sound? Why is it sound?

If you don't know what these terms mean, you need to check your course materials. including the "Philosophical Ethics: Almost Everything You Need to Know" page and this video (and this TikTok on syllogisms too): 



Argument 1:

Premise 1. Trump is currently president of the US. 

Premise 2. All current presidents are government employees.

Conclusion: Therefore, Trump is a government employee. 


Argument 2:

Premise 1. Biden is currently president of the US. 

Premise 2. All current presidents are government employees.

Conclusion: Therefore, Biden is a government employee. 


Argument 3:

Premise 1. Cows drive cars. 

Premise 2. If cows drive cars, then pigs fly airplanes. 

Conclusion: Therefore, pigs fly airplanes. 


Argument 4:

Premise 1. If abortion is morally wrong, then it's illegal. 

Premise 2. But abortion is not illegal. 

Conclusion: Therefore, abortion is not morally wrong. 


Argument 5: 

Premise 1. If it's prima facie wrong to eat meat, then it's prima facie wrong to wear fur coats. 

Premise 2. But it's not prima facie wrong to wear fur coats. 

Conclusion: Therefore, it's not wrong to eat meat. 


Argument 6 (if this argument is not valid, can you make it valid by adding a premise?)

Premise 1: Homosexuality isn't natural.

Premise 2:

Conclusion: Therefore, homosexuality is wrong. 


Argument 7:

Premise 1: If the death penalty reduces crime rates, then we should have the death penalty.

Premise 2: But the death penalty does not reduce crime rates.

Conclusion: Therefore, we should not have the death penalty.


The pattern, called "Denying the Antecedent":

If A, then B.

Not A.

Therefore, not B.

Can you make another argument of this pattern?

Can the premises be true but the conclusion false? Yes, and that means the argument pattern is invalid. 


Argument 8:

Premise 1: If experimenting on animals is wrong, then eating meat is wrong. 

Premise 2: And eating meat is wrong. 

Conclusion: Therefore, experimenting on animals is wrong. 


The pattern, called "Affirming the consequent":

If A, then B.

B.

Therefore A.

Can you make another argument of this pattern?

Can the premises be true but the conclusion false? Yes, and that means the argument pattern is invalid

More sample arguments in the pattern of syllogism are here. 

And more sample arguments to make logically valid by adding a premise to make into a syllogism:

An argument about drugs:

1. Many currently illegal drugs are dangerous.
2. ____________________________________
3. Therefore, many currently illegal drugs should be outlawed.

An argument about extra credit:

1. Extra credit helps students' grades.
2. ____________________________________
3. Therefore, we should have extra credit.

An argument about IVF:

1. Having children by IVF (in vitro fertilization) is unnatural. 
2. ____________________________________
3. Therefore, having children by IVF is wrong. 

An argument against homosexuality:

1. People who are homosexual cannot reproduce.
2. ____________________________________
3. Therefore, it it wrong to be homosexual. 

An argument about helping one's grandparents:

1. Eve can help her grandparents carry their groceries. 
2. Eve can easily help her grandparents carry their groceries. 
3. ____________________________________
4. Therefore, Eve is morally obligated to help her grandparents carry their groceries. 

Are the above arguments sound? What counterexamples -- when relevant -- can be used to show that they are not sound?

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