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Chapter 9
- Venn Diagrams
- Illustrate each of the Premises.
- For a Particular statement, put an X.
| I: Some P are Q |  |
| O: Some P are not Q |  |
- For a Universal statement, shade the area that is eliminated.
| A: All P are Q |  |
| E: No P are Q |  |
- Check to see if the diagram already shows the Conclusion.
I: Some P are Q
E: No C are P
O: Some C are not Q
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| Invalid, since the conclusion would appear as an X inside the C circle but outside the Q circle, like this: |  |
- If the diagram already shows the Conclusion, then the argument is Valid.
A: All D are F
E: No F are J
E: No D are J
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| Valid, since there cannot be anything that is D and J at the same time. | |
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