Arguments And Fallacies Flashcards
What is the Modus Ponens strategy?
It means ‘the mode that affirms by affirming’, represented as follows:
P → Q
P
Q
What is the Modus Tollens strategy?
It means ‘the mode that denies by denying’, represented as follows:
P → Q
~Q
~P
What is the Chain Argument strategy?
It is a chain of conditions, such as below:
A → B
B → C
~C
~B
~A
The last two are subsidiary conclusions
How do you represent the Either-Or Argument strategy?
It is an exclusive or, represented by the negation of the biconditional such as below:
~P ← → Q
P
~Q
What is the Conditional Argument strategy?
One with two conditionals in it and hence a conclusion which is itself a conditional such as below:
P → Q
Q → R
~R → ~P
What is the Reductio ad Absurdum strategy?
Arguing backwards from the falsity of the conclusion to the falsity of one of the premises, as if a valid argument has an obviously false conclusion, one or more of the premises must be false
What are the two ways an argument can be bad and their associated fallacies?
- Being invalid - formal or logical fallacies
- Being valid but with false premises - non-formal fallacies
What is the formal fallacy of Affirming the Consequent?
This closely resembles Modus Ponens, but involves a confusion of necessary and sufficient conditions such as below:
P → Q
Q
P
What is the formal fallacy of Denying the Antecedent?
This closely resembles Modus Tollens, but involves a confusion of necessary and sufficient conditions such as below:
P → Q
~P
~Q
What is the formal fallacy of the Undistributed Middle?
A syllogistic fallacy that occurs in predicate logic, wherein the term found in both of the premises doesn’t appear in both the predicate position and as the subject, but in the same position twice such as below:
Some A is B
Some C is B
Some A is C
What is the formal fallacy of Affirmative Conclusion from a Negative Premise?
This is a syllogistic fallacy where you deduce an affirmative conclusion from two negative premises, as at least one must be affirmative too such as below:
No A is B
w is ~A
w is B
What is the formal fallacy of Affirming a Disjunct?
This is falsely inferring from the fact that one element of a disjunct is true that the other is false such as below:
P v Q
P
~Q
This may be inferred via the Principle of Charity
What is the formal fallacy of The Equivocal Argument?
When an argument uses the same word with different senses, so may appear valid, but when the equivocation is exposed it becomes obviously not such as below:
In some countries men have a legal right to kill
In England, men do not have a legal right to kill
Not all humans have the same moral rights
What is the informal fallacy of The False Dilemma?
When two possibilities are presented as exhaustive, whereas there exists other possibilities, an unsound either-or argument
What is the informal fallacy of the Slippery Slope Argument?
It presents a small change now as leading inevitably large and undesirable change in future, and these can be sound or unsound
What is the informal fallacy of the Question-Begging Argument (petitio principii)?
One in which the conclusion repeats the premises in different words, so fails to prove anything that is not already assumed
What is the informal fallacy of the Circular Argument?
This is an expanded form of the question-begging argument, in which premises are only true if the conclusion is, so independent support for the conclusion cannot be provided, such as below in the Cartesian Circle:
‘If God exists, then whatever I clearly and distinctly perceive is true. God exists. Therefore whatever I clearly and distinctly perceive is true.’
What is the informal fallacy of Misplacing the Burden of Proof?
The burden of proof is on the person whose views go against common sense or the person asserting the existence of something, and this fallacy is wrongly establishing which side it lies on
What is the informal fallacy of Appeal to Common Practice?
The fallacy where you assume that because everyone thinks x means x is true
What is the informal fallacy of Appeal to Authority?
This is a fallacy as just because x thinks something doesn’t mean it is true, however sometimes it does, and this is context dependent:
If the Pope says contraception is sinful, this is more of a fallacy to argue than to argue for the advice of a doctor
What is the informal fallacy Ad Hominem?
This refers to arguments that seek to discredit an opponent’s character or qualifications rather than to refute his views
What is the informal fallacy of Crime by Association?
The fallacy whereby Group A makes the same claim as negatively viewed Group B, and therefore Group A are now negatively viewed, as below:
‘Every doctrine held by Hitler is wicked, and Hitler was a vegetarian, so vegetarianism is wicked’
What is the informal fallacy of The Straw Man?
This is the fallacy of refuting an argument different from one actually under discussion, whilst not acknowledging the distinction
What is the informal fallacy of Te Quoque?
This is a form of Ad Hominem, the appeal to hypocrisy to discredit someone else, such as below:
‘Jefferson was a slaveholder so we can disregard all his fine words about human equality and freedom’
Both can be true
