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Flashcards in Arguements Deck (16)
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1

Assuming that the premises are true is it possible for the conclusion to be false? If it is then the argument is invalid.

Test for validity

2

Assuming the premises are true, what degree of probability would they confer upon the conclusion

Test for probability

3

If P then Q
P
Therefore Q

Modus ponens (valid)
Affirming the antecedent

4

If P then Q
Not P
Therefore not Q

Denying the antecedent (invalid)

5

If P then Q
Not Q
Therefore not P

Modus Tollens (valid)
Denying the consequent

6

If P then Q
Q
Therefore P

Affirming the consequent (invalid)

7

In this form we have a conclusion that puts together information found in the premises.

syllogism

8

Arguing for the truth based upon what is generally true.

Statistical syllogism
Example: Only about 2% of high school students take philosophy. Tom is a high school student, so he doesn't take philosophy.

9

An argument involving polling a sample group and arguing that what is true of the sample group is true of the population as a whole.

Statistical generalisation
Example: 9 out of 10 Owners said their cats preferred wild mice to birds. Woof is a cat, so he will prefer wild mice to birds.

10

Relying upon the knowledge or testimony of others when something is beyond our experience and expertise.

Argument from authority
Example: I'm not going to eat red meat any more. My doctor said it eventually clogs the arteries and will lead to premature heart disease.

11

When we believe that there are enough similarities between two things and that what can be said of one can be said of another.

Argument from analogy
Example: Stealing from your employer is wrong; it's just the same as stealing from a shop.

12

Inference to the best explanation, is a method of reasoning in which one chooses the hypothesis which would, if true, best explain the relevant evidence. Abductive reasoning starts from a set of accepted facts and infers to their most likely, or best, explanations.

Abduction
Example: the sun appears to move across the sky. The best explanation we have for this is that the earth must rotate. Therefore, the earth rotates.

13

If P then Q
If Q then R
Therefore
If P then R

Hypothetical syllogism (valid)

14

Either P or Q
If P then R
If Q then S
Therefore
Either R or S

Dilemma (valid)

15

Either P or Q
If P then R
If Q then R
Therefore
R

Simplified Dilemma (valid)

16

Either P or Q
It is not the case that P
Therefore
Q

Disjunctive syllogism (valid)