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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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A sound argument _______ has a true conclusion.
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always
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A sound argument is a deductive argument that is (1) valid and (2) has all true premises. What does this imply about the conclusion?
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Every valid argument ______ has this feature: Necessarily, if its premises are true, then its conclusion is true.
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always
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Sound arguments are _______ valid.
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always
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A sound argument is a deductive argument that is (1) valid and (2) has all true premises.
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Valid arguments _______ have a true conclusions.
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sometimes
The premise(s) of a valid argument do lead conclusively to the conclusion but they might not be true. (Although every valid argument with true premises would have a true conclusion, valid arguments don't have to have true premises and, hence, don't all have true conclusions.) Examples: All gisbots are frammels. All frammels are boatwaps. So, all gisbots are boatwaps. All cows are flying creatures. All flying creatures are reptiles. So, all cows are reptiles. |
The premise(s) of a valid argument do lead conclusively to the conclusion but they might not be true. (Although every valid argument with true premises would have a true conclusion, valid arguments don't have to have true premises and, hence, don't all have true conclusions.)
Examples: All gisbots are frammels. All frammels are boatwaps. So, all gisbots are boatwaps. All cows are flying creatures. All flying creatures are reptiles. So, all cows are reptiles. |
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Valid arguments ____________ contain only false propositions.
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sometimes
Example: All cows are flying creatures. All flying creatures are reptiles. Therefore, all cows are reptiles. This is valid because the premises lead necessarily to the conclusion; if the premises were true (try to imagine such a world), it is obvious that that world would be such that cows were reptiles. |
Example:
All cows are flying creatures. All flying creatures are reptiles. Therefore, all cows are reptiles. This is valid because the premises lead necessarily to the conclusion; if the premises were true (try to imagine such a world), it is obvious that that world would be such that cows were reptiles. |
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Valid arguments with all true premises ___________ have a true conclusion.
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always
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A cogent argument ____________ has a false conclusion.
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sometimes
Although a cogent argument (strong with all true premises) has a conclusion judged to be probably true, it could in fact turn out to be false. |
Although a cogent argument (strong with all true premises) has a conclusion judged to be probably true, it could in fact turn out to be false.
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Deductive arguments that have all true premises and a true conclusion are __________ valid.
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Sometimes.
Do you remember this invalid structure: All A are C. All B are C. So, all B are C. Any argument with that structure is invalid. Obviously it is invalid here: All Dogs are Mammals. All Cats are Mammals. So, all Cats are Dogs. But the following example with all true parts is still invalid: All Dogs are Mammals. All Dalmatians are Mammals. So, all Dalmatians are Dogs. An invalid argument might “accidently” have a true conclusion even if the conclusion did not follow necessarily from the premise(s). Consider: Obama is President. Therefore, George Washington was the 1st. President. |
Do you remember this invalid structure:
All A are C. All B are C. So, all B are C. Any argument with that structure is invalid. Obviously it is invalid here: All Dogs are Mammals. All Cats are Mammals. So, all Cats are Dogs. But the following example with all true parts is still invalid: All Dogs are Mammals. All Dalmatians are Mammals. So, all Dalmatians are Dogs. An invalid argument might “accidently” have a true conclusion even if the conclusion did not follow necessarily from the premise(s). Consider: Obama is President. Therefore, George Washington was the 1st. President. |
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A cogent argument ____________ has a false premise.
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Never.
This follows from the definition of a cogent inductive argument: a strong argument with all true premises. |
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A deductive argument with true premises and a false conclusion is ________ valid.
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Never.
By definition a valid deductive argument is one that has this characteristic: if the premise(s) are or were to be true, the conclusion would necessarily have to be true. So a deductive argument with true premises that does not have a true conclusion violates the definition of a valid argument. |
By definition a valid deductive argument is one that has this characteristic: if the premise(s) are or were to be true, the conclusion would necessarily have to be true. So a deductive argument with true premises that does not have a true conclusion violates the definition of a valid argument.
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An invalid argument is ____________ sound.
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Never.
By definition a valid argument must be both valid and contain only true premises. So every invalid argument is unsound. |
By definition a valid argument must be both valid and contain only true premises. So every invalid argument is unsound.
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A deductive argument with all true premises and a true conclusion is _________ valid.
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Sometimes.
Do you remember this invalid structure: All A are C. All B are C. So, all B are C. Any argument with that structure is invalid. Obviously it is invalid here: All Dogs are Mammals. All Cats are Mammals. So, all Cats are Dogs. But the following example with all true parts is still invalid: All Dogs are Mammals. All Dalmations are Mammals. So, all Dalmations are Dogs. An invalid argument might “accidently” have a true conclusion even if the conclusion did not follow necessarily from the premise(s). Consider: Obama is President. Therefore, George Washington was the 1st. President. |
Do you remember this invalid structure:
All A are C. All B are C. So, all B are C. Any argument with that structure is invalid. Obviously it is invalid here: All Dogs are Mammals. All Cats are Mammals. So, all Cats are Dogs. But the following example with all true parts is still invalid: All Dogs are Mammals. All Dalmations are Mammals. So, all Dalmations are Dogs. An invalid argument might “accidently” have a true conclusion even if the conclusion did not follow necessarily from the premise(s). Consider: Obama is President. Therefore, George Washington was the 1st. President. |
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A cogent argument is ___________ weak.
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Never.
An inductive argument that is (1) strong and (2) has all true premises is cogent. |
A cogent argument is an inductive argument that is (1) strong and (2) has all true premises.
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Valid arguments are _______ sound.
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Sometimes.
Valid arguments do not always have all true premises. These valid arguments (they are valid because they have a valid structure) is not sound. [A sound argument is a deductive argument that is (1) valid and (2) has all true premises.] All gisbots are frammels. All frammels are boatwaps. So, all gisbots are boatwaps. All cows are flying creatures. All flying creatures are reptiles. So, all cows are reptiles. |
Valid arguments do not always have all true premises.
These valid arguments (they are valid because they have a valid structure) is not sound. [A sound argument is a deductive argument that is (1) valid and (2) has all true premises.] All gisbots are frammels. All frammels are boatwaps. So, all gisbots are boatwaps. All cows are flying creatures. All flying creatures are reptiles. So, all cows are reptiles. |
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A strong argument _______ has a false premise.
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Sometimes.
A strong argument has a conclusion that follows with at least 50% likelihood from the premises, but the premises may not be true. |
A strong argument has a conclusion that follows with at least 50% likelihood from the premises, but the premises may not be true.
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