Flashcards
B&K ch 3 (logic: deductive validity)
Cards in this deck (20)
- 1principle of charityif your sole interest is to discover the truth of things (and not just to persuade or refute people), we are most interested to discover good arguments. therefore we should always choose the best reconstruction of a given argument.
that way we discover reasons for accepting or rejecting particular propositions to the best of our knowledge - 2how to apply the principle of charity1. clarify what the arguer actually said
2. supplement what the arguer said (to make explicit what was merely implicit) - 3truth-valueis the proposition actually true? no = falsity, yes = truth.
- 4law of non-contradictionno proposition is both true and false
- 5deductive validityan argument is valid if and only if it would be impossible for it's premises to be true but its conclusion false
- 6prescriptive claimsclaims which state/express desires, norms or moral rules. these cannot be true or untrue, but they're susceptible to being called 'true' and 'false' because it's a matter of opinion.
e.g. 'the US needs a different health care system' - 7descriptive claimsfact--stating claims
e.g. 'jupiter is larger than saturn' - 8conditional propositionsmost characteristically expressed using the 'if-then' form of declarative sentences
e.g. 'if it is raining, then it is cloudy' - 9inclusive vs. exclusive words'either p or q' can be inclusive in the way that either P, Q, or both is/are true.
'P or Q' can be exclusive in the way that either P or Q is true, but never both - 10logical connectivesconnecting words, e.g. 'if-then', 'either-or', 'unless'
- 11chain argument (aka 'hypothetical syllogism')when all propositions + the conclusion have an 'if-then' structure
- 12modus ponensp1) if p then q
p2) p
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c) q - 13modus tollensp1) if p then q.
p2) not-q
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c) not-P - 14syllogism meaningeen redenering die bestaat uit drie proposities: twee premissen en een conclusie. vier soorten proposities (A, E, I, O)
- 15disjunctive syllogismexpressing a choice between two mutually exclusive possibilities, thus:
P1) P or Q.
P2) not-P.
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C) Q. - 16refutation by counterexamplea method of criticising an argument by fabricating another argument in the same form, but which is clearly wrong
- 17in a venn diagram, which symbol is used to say 'at least one entity and possibly all'?X
- 18in a venn diagram, what does a line (that goes through at least 2 areas) mean?at least one entity in one of these areas, unclear in which one and might be in both
- 19categorical propositionspropositions that contain categories, eg. 'swimmers', which include humans, fish, etc. (both are also categories)
- 20categorical syllogismany argument which is composed of two premises in the form of categorical propositions and a conclusion which is also a categorical propositions. total of three categories.
e.g. P1) all pets are animals.
P2) some fish are not pets.
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C) some fish are not animals.
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- SSR Flashcards on B&K ch 3 (logic: deductive validity), created by Sabine - on 20/09/2020.
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