Validity and Soundness: Additional Exercises

1. Validity and Soundness:Additional Exercises 2007 Makoto Suzuki

2. Validity and Soundness, once again • Instructions: For each of the following arguments, determine whether or not it is valid and whether or not it is sound.

3. Question 1 • Gloria is an adolescent because all adolescents are grumpy and Gloria is grumpy. • Valid or invalid? • Invalid. • This argument has the following fallacious argument form, where the capital letters are the variables that take general terms as values and a is a particular thing: All F are G. a is G. ————— a is F. • Sound or unsound? • Unsound • Invalid arguments are necessarily unsound.

4. Question 2 • Some Muslims are fundamentalists. Some fundamentalists are dangerous. Hence, some Muslims are dangerous. • Valid or invalid? • Invalid. • Sound or unsound? • Unsound.

5. Question 3 • All wasps are unfriendly. No puppies are wasps. Therefore, no puppies are unfriendly. • Valid or invalid? • Invalid • This argument has the following fallacious argument form: All G are H. or No F are G. No F are G. All G are H. —————————— No F are H. No F are H. • Sound or unsound? • Unsound.

6. Question 4 • Every upright person is believable. No man is believable. Therefore, no upright person is a man. • Valid or invalid? • Valid. • This argument has the following valid argument form: All F are G. No H are G. ————— No F are H. • Sound or unsound? • Unsound. • The second premise is false!