Preparatory Chapter

Discussion Questions

Preparatory Background: Logic for Metaphysics

For questions 1–4, determine whether the arguments are enthymemes or simply invalid. If they are enthymemes, provide the missing premise so as to make the argument valid as stated.

1.  
   1. Suffering exists in the world.

      Therefore,

   2. God does not exist.
2. 1. The store closes at 4pm.
   2. It's dark outside.

      Therefore,

   3. The store is closed.
3. 1. Serena and Stephanie are both wearing blue shirts.

      Therefore,

   2. None of the girls in the room are wearing red.
4. 1. Leslie is a bachelor.
   2. Leslie is red-headed.

      Therefore,

   3. Some men are red-headed.

For questions 5–6, determine why the argument is unsound.

5. 1. All vixens are foxes.
   2. All foxes wear sneakers.

      Therefore,

   3. All vixens wear sneakers.
6. 1. If Rachel plays basketball, then she is an athlete.
   2. If Rachel is an athlete, then she wears sneakers.

      Therefore,

   3. If Rachel plays basketball, then she wears sneakers.
7. Describe a real-life example of someone's failure to employ the principle of charity. 
8. Explain in your own words the relationship between truth and validity.
9. Provide a set of claims that seem to support a claim but that do not constitute a valid argument. How can you modify them to make a valid argument?
10. Consider this argument for substance dualism (from http://plato.stanford.edu/). Is this argument valid? Is it sound?
1. It is imaginable that my mind could exist without my body.
2. Therefore, it is conceivable that my mind could exist without my body.
3. Therefore, it is possible that my mind could exist without my body.
4. Therefore, my mind is a different entity from my body.