Task 2 - Hurley chapter 1 Flashcards
Logic
The organized body of knowledge, or science that evaluates arguments
- allows us to distinguish good arguments from bad ones
- father of logic: Aristoteles “syllogistic logic and moral logic
Argument
a group of statements, one or more of which (the premises) are claimed to provide support for or reasons to believe one of the others (conclusion)
good argument
premises support the conclusion
bad argument
do not support conclusion
truth values
Truth and falsity of a statement –> many sentences cannot be said true or false
eg. questions.
Premises indicator
- Since
- As indicated by
- Because
- For
- In that
- May be inferred from
- As
- Given that
- Seeing that
- For the reason that
- In as much as
- Owing to
conclusion indicator
- Therefore
- Wherefore
- Thus
- Consequently
- We may infer
- Accordingly
- We may conclude
- It must be that
- For this reason
- So
- Entails that
- Hence
- It follows that
- Implies that
- As a result
Inference
reasoning process exposed by an argument
used interchangeably with an argument
Preposition
the meaning or information content of a statement
recognizing arguments
- not nessesary that premises present actual evidence or true reasons or that they support the conclusion –> only has to claim to have evidence or reason s support or imply something
two conditions must be fulfilled for a passage to prove something
1. factual claim
2. intentional claim
factual claim
at least one of the statements must claim to present evidence or reason
inferential claim
the claim that the passage expresses a certain kind of reasoning process- that something supports or implies something or that something follows from something
explicit
implicit
inferential claim explicit
assessed by premises or conclusion indicator works (thus, since, because, hence, therefore
implicit
inferential relationship between the statements in a passage nut the passage contains no indictor word. to find argument insert therefore
Single non inferential passage
Unproblemtic passage that lack a claim that anything is being proven
- contains statement that could be premises or conclusion (or both) BUT missing the claim that a premises supports a conclusion or conclusion has supported by premises
e. g. - warning
- piece of advice
- statement of belief/opinin
- loosely associated statement: lack a claim that one of them is proven by the other
- report
Expository passage
Kind of discourse that begins with a topic sentence followed by another sentence that develop the topic sentence
- when following sentence is not aiming at proving the topic sentence than no argument
- only expand it for elaborate it
expository passage example
• Ex: There are three familiar states of matter: solid, liquid, and gas. Solid objects ordinarily maintain their shape and volume regardless of their location. A liquid occupies a definite volume, but assumes the shape of the occupied portion of its container. A gas maintains neither shape nor volume. It expands to fill completely whatever container it is in
illustrations
an expression involving 1+ examples that is intended to show what something means or how it is done
Argument: if it is something everyone accepts its most likely not an argument
illustrations examples
• Ex: Chemical elements, as well as compounds, can be represented by molecular formulas. Thus, oxygen is represented by “O2,” water by “H2O,” and sodium chloride by “NaCl.” not an argument = no claim
• Arguments from example = illustrations that are arguments
o Ex: Although most forms of cancer, if untreated, can cause death, not all cancers are life-threatening. For example, basal cell carcinoma, the most common of all skin cancers, can produce disfigurement, but it almost never results in death.
Explanations
an expression that purports to shed light on some event or phenomenon
2 components
1. explanandum
2. explanans
argument: explanation has purpose to explain why not to prove anything
explanandum
the statement that describes the event or phenomenon to be explained (explanation )
explanans
the statement pr group of statements that purports to the explaining (Explanation)
examples explanation
Ex: The sky appears blue from the earth’s surface because light rays from the sun are scattered by particles in the atmosphere
• Ex: Women become intoxicated by drinking a smaller amount of alcohol than men because men metabolize part of the alcohol before it reaches the bloodstream, whereas women do not explanation + argument
Conditional statemnets
if … then … statements
2 components: antecedent and consequent
- a single conditional statement is not an argument
- a conditional statement may serve as either premises or conclusion or both of an argument
- re-expression of inferential content of conditional statement to form argument
(when conditional statement and another statement come together may form an argument)
sufficient condition
necessary condition
antecedent (conditional statement)
statement immediately following if
consequent (conditional statement)
following the then
sufficient condition
all you need is a for occurrence of b
e.g. being a dog is sufficient condition for being an animal
necessary condition
a cannot occur without b
e.g. being an animal is a necessary condition for being a dog
deduction
if the conclusion is claimed to follow with strict certainty or necessity
e.g. The meerkat is a member of the mongoose family. All members of the mongoose family are carnivores. Therefore, it necessarily follows that the meerkat is a carnivore.
more info see table in summary
induction
if it is claimed to follow only probably –> probabilistic reasoning
e.g The meerkat is closely related to the suricat. The suricat thrives on beetle larvae. Therefore, probably the meerkat thrives on beetle larvae
More info see table in summary
indicator words deduction
necessarily impossible (im)plausible (un)likely reasonable to conclude
indicator words induction
Probably, certainly, absolutely, definetly
Valid deductive arguments
and argument in which ut is impossible for the conclusion to be false given that the premises are true
- the conclusion follows with strict necessity from the premises
invalid deductive argument
argument in which it is possible for the conclusion to be false given that the premises are true
- the conclusion does not follow which strict necessity from the premises
How to test validity
- assume that all the premises are true
- determine if it is possible, with the assumption for the conclusion to one false
- determine by the relationship between the premises and conclusion
- do the premises support the conclusion?
sound argument
a deductive argument that is valid and has all true premises
unsound arguments
a deducive argument that is invalid and has 1+ false premises or both
Strong inductive premises
argument in which it is improbable that the conclusion be false given that the premises are true +
weak inductive arguments
an Argument in which the conclusion does not follow probably from the premises, even though it is claimed to
uniformity of nature
the future tends to replicate the past and regularities that prevail one spatial region tend to prevail in other regions
• Bias in our judgement
• Ex: In the past sugar has always tasted sweet according to the uniformity of nature, sugar will continue to taste sweet in the future
testing the strength of arguments
- assume the premises are true
- determine wether based on the assumption the conclusion is probably true
- strength or weakness of inductive argument results from the probabilistic support the premises give to the conclusion
- total evidence requirement
total evidence requirement
the premises must exclude or overlook some crucial pieces of evidence that undermines the state premises and requires a different conclusion
if not met –> an argument might habe literally true premises and a probably false conclusion and still be strong
content argument
an inductive argument that is strong and has true premises
un-cogent argument
an inductive argument that is weak and has 1+false premises
argument form
validity of a deductive argument is determined by this
- sometimes valid deducive arguments don’t have a recognizable form –> they are incomplete, the form is not explicit
- when argument completed and correctly phrased : form becomes apparent
Valid: all a are b. all B are C, All A are C
Invalid: All A are B. All C are B. All A are C
substitution of words into argument to check this
counterexample
substitution instance having true premises and false conclusion
Counterexample method
Isolation teh form of an argument and the constructing a substitution instance having true premises and false conclusions
- can prove the invalidity of an invalid argument but cannot prove validity
e. g. Since some employees are not social climbers and all vice presidents are employees, we may conclude that some vice presidents are not social climbers
Vertikal pattern
a series of arguments in which a conclusion of a logically ptior argument becomes a premise of a subsequent argument
Statement 1 is supported by 2 which in turn by 3 which in turn is supported by 4
Horizontal pattern
a single argument in which two or more premises provide independent support for a single conclusion
- if one of the arguments is taken away all the other ones would still support the conclusion
statement 2,3 and 4 support 1 independently
2 variations: conjoint conclusion and multiple conclusion
Conjoint conclusion
occurs when the premises depend on one another in such a way that if one were omitted the support that the other provide would be diminished or destroyed
statement 1 is the conclusion
2 and 3 alone only weak support but both together they provide support
–> 2 and 3 support 1 conjointly
multiple conclusion
when 1+ premises support multiple conclusions
statement 1 supports both 2 and 3
- since no single argument can have more than one conclusion, the passage is correctly evaluated as consisting of two arguments
