the process of reasoning from premises to conclusions
inference
the study of arguments
logic
what makes an argument good? (2)
1. premises are true
2. premises must be related convincingly to the conclusion
T/F there are subtypes of inference
T
arguments in which the truth of the premises ideally provide a guarantee of the conclusion's truth.
deductive
T/F deductive arguments can say more than what was present in their premises
F
a deductive argument of 2 premises and a conclusion
syllogism
statements asserting relationships between or within classes or groups of things
categorical statement
T/F most categorical arguments contain all/none/some/etc
T
statement in which either one or the other component is asserted true
disjunctive
T/F disjunctive statements usually have either/or
T
statements containing a hypothetical
conditional
two parts of a conditional statement
given P: antecedent (if P) and consequent (then Q)
2 properties of good deductive arguments
validity and soundness
conditions for validity:
iff premises T, then conclusions T
T/F an argument is valid if it is impossible that using valid premises provides a false conclusion
T
T/F validity depends on the actual content of the argument
F (only structure)
2 common forms of valid argument
modus ponens and modus tollens
"the way that affirms via affirming"
modus ponens
Structure of a modus ponens argument
1. If P, then Q.
2. P exists
-> Q.
T/F affirming the consequent is a valid argument
F
form of an "affirming the consequent" argument
1. If P, then Q
2. Q
-> P (invalid)
"the way that denies via denying"
modus tollens
form of modus tollens argument:
1. If P, then Q.
2. Not Q.
-> not P
synonym for modus tollens
denying the consequent
T/F denying the antecedent is a valid argument
F
structure of denying the antecedent
1. If P, then Q
2. Not P.
-> Not Q.
validity + true premises
sound argument
T/F validity and true premises do not guarantee true conclusions
F
T/F arguments can be valid but not sound
T
T/F validity and soundness can refer to statements
F
an argument that reiterates the truth or falsity of a single statement
tautology
T/F tautology is a valid argument
T
T/F tautology is a sound argument
T
T/F tautology is a good argument
F
T/F If P, then Q, and given Q necessarily implies P.
F
logical defect in an argument
fallacy
T/F if an argument is fallacious, its premises do not decisively support its conclusion
T
T/F fallacies include false statements
F
T/F fallacies include bad reasoning
T
2 categories of fallacy
formal and informal
defect in the structure of an argument
formal fallacy
examples of formal fallacy
denying the antecedent, affirming the consequent
T/F inductive arguments can also be formally fallacious
T (they can be weaker then they claim)
fallacy not attributable to form
informal
conclusion is derived from premises that presuppose its own truth
begging the question
other names for begging the question (4)
circular reasoning, vicious circle, circulus in probando, petito principii
argument which paraphrases the premises in the conclusion
begging the question
Type of argument:
If God exists, then the Bible is His word
God exists
The bible is the word of GodÂ
If the bible is the word of God, God exists
-> God exists.
begging
argument based on premises irrelevant to the argument's conclusion
argumentum ad hominem
other name for ad hominem
fallacy of personal attack
2 kinds of ad hominem
abusive (qualities of the person), circumstantial (circumstances)
T/F ad hominem arguments are only fallacious if they're negative
F
T/F if the quality of the person in question is a premise in the argument, then the argument is not ad hominem
T
T/F it's fallacious to doubt the plausibility of someone's testimony regarding a claim even if we accept the claim itself
False. It's perfectly acceptable to wonder if there are ulterior motives.
argument which hinges on ambiguous terms
fallacy of equivocation. These are usually jokes or wordplay regarding alternate meanings
argument which depends upon ambiguous phrasing (e.g. misplaced modifiers)
amphiboly
argument which causally connects A -> B-> C -> D -> ... Z without supporting any of the links in between
slippery slope
T/F all long causal arguments are slippery-slope
F
argument which relies upon someone's "expert" testimony
argument from authority
other name for argument from authority
argumentum ad verecundiam
T/F all arguments from authority are fallacious
F
T/F if argument from authority is unnecessary, the argument is weakened
T
T/F if there is no authority on a subject, then argument from authority is still valid
F
T/F Bias can weaken an argument from authority
T
T/F holding decidedly non-mainstream positions increases the probability that the argument is weak
T
arguments which attempt to (dis)prove statements from the fact that there is no evidence for/against it
argument from ignorance
other name for argument from ignorance
argumentum ad ignorantium
T/F scientific research often relies on the argument from ignorance
T
fallacy which requires that option A be the only possibility because it is the only option we know of
Only Game in Town Fallacy
T/F it's fallacious to assume that an argument containing a fallacy produces a false conclusion
