Exercises on Categorical Syllogism

The Categorical Syllogism Logic Exercises

GENERAL INSTRUCTIONS: 1. Highlight this post, copy and paste to MS Word NEW DOCUMENT, then save it to the computer. 2. Attach this MSdoc file to your email to be forwarded to jcgarcia_ndtc@yahoo.com on or before May 4. 2012. Indicate a) whether the following arguments are valid or invalid by checking the appropriate square. Also, if the syllogism is invalid indicate which rule of logic was violated. To make this easier, use the following steps: Step 1: Circle the middle term. Step 2: Determine what kind of statement (i.e., A, I, E, or O) is the first premise. Then do the same for the second premise. Finally, determine what kind of statement is the conclusion. Step 3: Highlight all the distributed terms using a colored highlighter. Step 4: Check to see if the middle term is distributed at least once. If it is not, no need to proceed further, the syllogism is invalid. Step 5: If there are any distributed terms in the conclusion, check to see if those very terms are distributed in the premises. Step 6: Check the rest of the rules. If no rules are violated, the syllogism is valid. 1. Some Lifeissues.net readers are philosophers. Sean is a philosopher. Ergo, Sean is a Lifeissues.net reader. Valid [ ] Invalid [ ] Reason: 2. No man is perfect Some men are presidents. Ergo, some presidents are not perfect. Valid [ ] Invalid [ ] Reason: 3. All matter obeys wave equations. All waves obey wave equations. Ergo, all matter is waves. Valid [ ] Invalid [ ] Reason: 4. All that is good is pleasant. All eating is pleasant. Ergo, all eating is good. Valid [ ] Invalid [ ] Reason 5. All patriots are voters. Some citizens are not voters. Ergo, some citizens are not patriots. Valid [ ] Invalid [ ] Reason: 6. All A are B Some C are not B. Ergo, some C are not A. Valid [ ] Invalid [ ] Reason: 7. No oak trees bear fruit. No maple trees bear fruit. Therefore, no oak trees are maples. Valid [ ] Invalid [ ] Reason: 8. All scientific knowledge is a work of reason. All scientific knowledge is true. Ergo, all that is true is a work of reason. Valid [ ] Invalid [ ] Reason: 9. All C are B All T are B Ergo, all T are C Valid [ ] Invalid [ ] Reason: 10. All chickens are born from eggs. All turkeys are born from eggs. Ergo, all turkeys are chickens. Valid [ ] Invalid [ ] Reason: 11. Nothing easy is worthwhile. Nothing good is easy. Ergo, nothing good is worthwhile. Valid [ ] Invalid [ ] Reason: 12. All contraceptives acts are for avoiding pregnancy. All use of NFP is for avoiding pregnancy. Ergo, All use of NFP is contraceptive. Valid [ ] Invalid [ ] Reason: 13. All parts of a living organism are inside the body. The fetus is inside the (mother's) body. Therefore, the fetus is a part of the living organism (mother's body) Valid [ ] Invalid [ ] Reason: