3. No Valid Syllogism Can Have Two Negative Premises
If both premises are negative, they tell us that both the major
and the minor term are excluded, wholly or in part, from the
middle term. And that does not tell us how the major and minor
terms are related to each other.
Example:
Knowing that no chiropractor has sung for the Metropolitan Opera,
and that no one who has sung for the Metropolitan Opera has been
in Kuala Lumpur, does not tell us that no chiropractors have been
in Kuala Lumpur, or that some have, or anything else.
| 1. | Is an A proposition affirmative or negative? | ||
| a) | It is affirmative. | ||
| b) | It is negative. | ||
| 2. | Is an O proposition affirmative or negative? | ||
| a) | It is affirmative. | ||
| b) | It is negative. | ||
| 3. |
Does the following syllogism have two negative premises? No A are B |
||
| a) | yes | ||
| b) | no | ||
| 4. |
Does the following syllogism have two negative premises? No one who competes for money is an amateur |
||
| a) | yes | ||
| b) | no | ||
| 5. |
Does the following syllogism have two negative premises? Some crimes against property are frauds |
||
| a) | yes | ||
| b) | no | ||
| 6. |
Does the following syllogism have two negative premises? Some M are not P |
||
| a) | yes | ||
| b) | no | ||
| 7. |
Does the following syllogism have two negative premises? Some P is not M |
||
| a) | yes | ||
| b) | no | ||
|
| © Copyright 1998, W.W. Norton & Co. |