D265 Notes Critical thinking
critical Thinking Terms:
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Premise – The statements being offered in support of the conclusion.
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Conclusion – is the statement being argued for.
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Non–Propositions – are not statements about matters of fact (or
fiction). They do not make a claim that can be true or false.
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Deductive Arguments – Arguments where the premises
guarantee or necessitate the conclusion. Leaves no question or
possibility.
o
Example: All rabbits have long ears. Bugs is a rabbit.
Consequently, Bugs has long ears.
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Inductive Arguments – Arguments where the premises make
the conclusion probable. (I think)
o
Example: Because most penguins are from areas with cold
climates, it is probable that the penguin you saw at the zoo was
from an area with a cold climate.
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Abduction Arguments – Arguments where the best available
explanation is chosen as the correct explanation.
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Validity – In a good deductive argument structure, true premises
make the conclusion necessarily true.
o
Example: When I went outside this morning, the grass was
completely covered with dew. It must have rained last night.
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Valid Argument – It is not possible that the conclusion is false
when the premises are true.
o
Example: Ralph is a dog. No dogs are allowed on the roller-
coaster. Therefore, Ralph is not allowed on the roller-coaster.
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Invalid Argument – An argument is invalid when its conclusion is not
proven by its premises.
o
Example: If I am President then I am famous. I am not
President. Therefore, I am not famous.
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Sound Argument – A sound argument is valid and has true premises.
o
Example: All whales are mammals. Killer Whale is a whale.
Therefore, Killer whale is a mammal.
o
Example: All Planets in our solar system orbit the sun. Mars is a
planet in our solar system. Therefore, Mars orbits the Sun.
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Unsound Argument – An argument is unsound when it is either
invalid or has one or more false premises.
o
Example: All dogs are mammals. Therefore, dogs are
cows. CONGENCY
