Critical Thinking
Disagreeing
"That's not true." "I don't think so." "Actually" "I think..."
Confirms, false and true
(Universal) A,E (All and No) Confirms or false (Particular) I,O (Some and Some Not) Proves true
Premise Indicators
-Because -The reason is? -But and and (show multiple premises) First, second, third, Finally...
Adding (agree and adding)
-Can be same or new topic "I don't think so either" I know how you feel..
Subcontraries (across bottom)
-Can both be true but no both false.
INDUCTIVE
-Claim to be strong not valid -can be strong or weak (Inductive, in strong, in weak)
Subalternation
-Down the sides *Truth flows down *False flows up false floats up Truth sinks down
DEDUCTIVE
-Have strongest claim: validity Not all are valid.
Contradiction (Diagonal)
-One always true the other always false.
ContrApOsition
-Switch and negate (opposite) -only valid for A and O (All and Some Not)
ConvErsIon
-Switches the subject and predicate. -only valid for E and I (No and Some)
Conclusion Indicators
-This is evident that... -Hence -therefore -It obviously follows that... -So, -Thus -Consequently
Observation
-Valid for all forms -Changes All to No or -Changes Some to Some Not
Contraries (across top)
-can both be false but not both true.
To determine the conclusion
1. Find the indicator word 2. Is the indicator a conclusion or primes indicator -Generally indicators point forward or can be in the middle of the statement.
Square set up
A (All)........................... E (No) I (Some)...................... O (Some Not) Universal on top Particular on bottom
Universal Forms
A and E (All and No)
Cogent
A strong inductive argument with TRUE premises. Cogent=strong+True premises UNcogent=weak or false premises
Validity
A valid argument is such that if the premises were true then the conclusion would also be true. (Premises MAKE the conclusion true. Even if the premises are NOT true.) ARGUMENT CAN BE VALID AS LONG AS THE REASONING IS LOGICAL. ALL or nothing, no degrees of validity.
Form A
All
Challenging (Asking for justification WITHOUT disagreeing)
Asking for the reason.... What evidence/reason.... What makes you think... How do you know.... Can you give me a reason... Why would you think that...
Clarifying (asking that the speaker make the claim more precise)
Asking what do you mean by... I've never heard of.... Do you mean A or do you mean B? What exactly do you mean? I really have no idea what you are talking about.
What is an argument?
Consists of one or more statements (premises) which are claimed (inferential claim) to be an objectively good reason to believe another statement (conclusion).
Disjunctive Statements
Contain "or" A or B.
Disagrees with the conclusion
Disagrees with the conclusion
Disagrees with the conditional premise
Disagrees with the first premise
Disagrees with the Other premise
Disagrees with the second premise
Particular Forms
I and O (Some and Some Not)
Hypothetical Syllogism
If A then B*. If B* then C. If A then C. And If A* then B. If C then A*. If C then B.
Modus Ponens
If A then B. A. B. Invalid: If A, then B. B.** A.**
Modus Tollens
If A then B. Not B. Not A. Invalid If A then B. Not A.** Not B.**
Invalid Hypothetical Syllogism
If A* then B. If A* then C. If B then C. and If A then B*. If C then B*. If A then C. The A and B can not line up on first two lines.
ARGUMENTS
Inductive -Weak -strong *cognet Deductive -invalidity -Valid *Sound
All arguments are divided into two groups:
Inductive and deductive
Strong
Is such that the truth if the premises makes the conclusion PROBABLY true. -Can have degrees of Strength.
Weak
Is such that the truth of the premises DOES NOT make the conclusion likely to be true. -Can have degrees of weakness
Commits the circumstantial Fallacy
Makes issue of personal motives
Commits the Fallacy of Abuse
Name calling
Form E
No
A single Particular example that mathces
Proves true
QUIZ 1
QUIZ 1
QUIZ 2
QUIZ 2
QUIZ 4 Logical forms A,E,I,O
QUIZ 4
QUIZ 5 Conversion, Contraposition, Observation
QUIZ 5
QUIZ 6 Square of Opposition
QUIZ 6
QUIZ 7
QUIZ 7
QUIZ 8 Responding to arguments
QUIZ 8
QUIZ 3
Quiz 3
Invalidity
Regardless of truth an argument can still be invalid. Invalidity means faulty reasoning.
Form I
Some
Form O
Some NOT
Sound vs Cognet
Sound=valid+true premiseS unsound=invalid or false premise Cogent=strong+True premises UNcogent=weak or false premises
A deductive argument cannot be almost valid.
True
A deductive argument cannot be half valid
True
All cogent arguments are strong.
True
All sound arguments have a true conclusion
True
All sound arguments have true premises.
True
An Argument's being sound implies that it is valid.
True
An argument must have 2 or more premises.
True
An argument with all true premises and a false conclusion cannot be valid
True
An argument's being invalid implies that it is sound.
True
An argument's being invalid implies that it is unsound
True
An argument's being sound implies that it is valid
True
Arguments with false conclusions are never sound.
True
Cogent inductive arguments have true premises.
True
Deductive arguments are either valid or invalid
True
Every argument makes an inferential claim.
True
False sentences are statements.
True
If all premises are true and the conclusions is false, then the argument cannot be valid.
True
If an argument is strong and has true premises, then the conclusion is probably true.
True
If an argument is uncogent but strong, then it must have false premises.
True
If an argument is weak then it cannot be cogent.
True
Some inductive arguments are stronger than others.
True
Some inductive arguments are weaker than others
True
Some inductive arguments are weaker than others.
True
Some inferential claims are false.
True
Some valid arguments have false conclusions.
True
The conclusion of a strong argument with true premises will be probably true.
True
The difference between an inductive and a deductive argument is in the kind of inferential claim they make.
True
The inferential claim of an inductive argument is that the conclusion is probably true given the premises.
True
if an argument is valid and has true premises, then the conclusion cannot be false.
True
An argument must have at least one premise.
True (An argument must have one or more premises.)
A valid argument would be unsound if it had false premises.
True (Having false premises in one way to be unsound. Unsound=invalid or has at least one false premise.)
If an argument is uncogent and has true premises, then it must be weak.
True (If it were strong with true premises it would be cogent.)
The conclusion of a valid argument with true premises will be true.
True (That's basically what "valid" means)
All invalid arguments are unsound.
True Unsound=invalid or false
Unsound
When an argument is invalid and/or has at least one false premise unsound=invalid or false premise
Sound arguments
When an argument is valid AND has true premises. Sound=valid+true premiseS
Premises
claims that are to be objectively good reason to believe another statement (the conclusion)
A single Universal example that matches only
confirms.
A single Universal form that states the opposite proves
false
Inferential claim
is usually implicit (implied) rather than explicit (stated). No inferential claim, no argument
Deductive arguments are either valid or invalid.
true
Some inferential claims are false
true
Sound deductive arguments always have true conclusions.
true
