Ctaea: Ch. 5 - Formal Logic

Front 1

classical structure of an argument:

Back 1

logical form that an argument should take.

Front 2

syllogism:

Back 2

basic structure of an argument, deductive reasoning - conclusion is included from the beginning.

Front 3

Syllogism's 3 parts:

Back 3

1. Major premise (reasoning linking 2 &3)
2. minor premise (support)
3. conclusion (claim being made)

Front 4

"all human beings are mortal"

Back 4

major premise

Front 5

"socrates is a human being"

Back 5

minor premise

Front 6

"therefore, socrates is mortal"

Back 6

conclusion

Front 7

enthymeme:

Back 7

argument that is missing at least one part of the syllogism, comes to a probably conclusion, or does both.

Front 8

inductive reasoning:

Back 8

any argument that comes to a probably instead of a an absolute conclusion, or that reasons from known premises to an unknown conclusion

Front 9

enthymeme example:

Back 9

all human beings are mortal,
hilary appears to be a human being,
therefore, hilary is probably normal.

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material truth:

Back 10

argument reaches a truthful conclusion, or uses true premises, as much as "truth" can be determined.

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formal validity:

Back 11

the argument has the correct structure or "form"

Front 12

don't think reasoning in an argument is valid just because...

Back 12

you believe the conclusion to be true.

Front 13

sound or cogent argument:

Back 13

an argument that is both logically valid and uses materially true premises

Front 14

categorical syllogism:

Back 14

establishes categories in which the subject of the minor premise should fit, it's major premise uses absolute or universal terms ("all", "every", "always")

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7 requirements of categorical syllogism:

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1. categorical syllogism must have exactly three "terms" (major, minor, middle)
2. every term must be used exactly twice.
3. a term may be used only once in any premise.
4. middle term must be used in an unqualified or a universal sense.
5. a term may be in the conclusion only if it has been in the major or minor premise.
6. at least one of the premises must be stated in a positive way.
7. if one premise is negative, then the conclusion must be negative.

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disjunctive syllogism:

Back 16

major premise presents 2 or more mutually exclusive (you can have one alternative, you can't have more than one at the same time) alternates.

Front 17

in valid disjunctive syllogism, the minor premise must...

Back 17

either accept one of the alternative sin the major premise or reject all but one of the alternatives. (once that choice is made, conclusions must either reject all of the remaining choices or accept the only alternative not rejected.

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to determine formal validity of a disjunctive syllogism:

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don't consider whether premises are correct, consider whether conclusion logically follows assuming the premises are correct.

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hypothetical syllogism (conditional):

Back 19

major premise presents a hypothetical condition and its outcome.

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2 basic forms of a valid hypothetical syllogism:

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1. if antecedent, then consequent. affirm antecedent. therefore, affirm consequent.
2. if antecedence, then consequent, deny consequent, therefore deny antecedent.

Front 21

1st requirement for a valid hypothetical argument:

Back 21

minor premise must either accept the antecedent or contradict the consequent.