class 1 Flashcards
logic
the formal study of valid reasoning
(or inference), “formal” as it is interested in the forms of
inferences
reasoning
the process whereby we draw
(infer) conclusions from premises
forms
the general– repeatable and empty – models or structures of reasoning
* Empty = without content
* Repeatable = adaptable to any context and any content
argument
an inference (from premises to
conclusion) which is presented in public. an inter-personal, confrontation with the aim of
convincing that the conclusion is true (is to be believed)
arguments (dialogic form)
- Jones – Brown won’t be elected (T1)
- Smith – Why do you think so?
- Jones – Because he does not use social media (T2)
- T2 = premise; T1 = conclusion
arguments (monologic form)
- Brown won’t be elected (T1) because he does not use the social
media (T2) - Brown does not use the social media (T2), and therefore he won’t be
elected (T1)
justification
the relation between premises and conclusions
Justifying = giving (themselves or other people) reasons to believe
supporting – grounding– justifying– proving = different ways of similar procedures
difference between justification and explanation
I cannot come by car (T1) because my car is broken (T2)
justification is a process of convincing someone who does not believe your conclusion
irrelevant reasons
no relation to the
target thesis (the conclusion)
- Venus is a planet, therefore today is 09.16.2024 (?)
weak reasons
there could be some relation, but there are more or less evident counter-reasons (counter-examples)
- Amal is Egyptian, so she’s Muslim
- (many Egyptian are not Muslim)
proving (or ‘demonstrating’)
giving strong (logical) justifications - there is no counter-reason, no counter-example (ideally)
valid
formally adequate
sound
valid + premises that are true in our
world
syntactic validity
based on language, ‘adequate’ in virtue of the meaning of the words we use
An inference is syntactically valid if and only if it respects the universal rules of the language in which it is
expressed
semantic validity
based on truth, ‘adequate’ in virtue of the truth value of the premises
An inference is semantically valid if and only if in any possible world in which the premises are true the
conclusion is true too
validity
truth-preservation from premises to
conclusions in any possible world
features of a good argument
- valid: if it is formally adequate
- sound: if it is valid + has premises that we acknowledge as true in our world
- strong: if it is not easy to find counter-reasons
- convincing: if it is apt to persuade the audience (we do not always accept the rational constraint of a sound argument)
- context- and content-sensitive: if it fits the situation in which it is presented
strong reason
there are no (evident) counter reasons
