Unit 3: Syllogisms and Validity Flashcards
Define argument
A set of statements,
one** of which appears to be **implied** or **supported
by the others
The _____________ of an argument is the statement that appears to be implied by the other statements in the argument, which are called ____________.
conclusion
premises
Define syllogism
A deductive argument
with two premises** and **three terms
What is a categorical syllogism?
A syllogism consisting of
three statements
in categorical form
What is the major term of a syllogism?
The predicate of the conclusion
and is used in one premise
What is the minor term of a syllogism?
The subject of the conclusion
and is used in the other premise
What is the middle term of a syllogism?
The term that is found once in each premise
What is the major premise?
The premise that contains the major term
What is the minor premise?
The premise that contains the minor term
What are the 5 steps
to put a syllogism into standard form?
- Find the conclusion
- Find the major term
- Find the major premise
- Find the minor premise
- Write the syllogism in standard order
The ____________ of a syllogism
is a representation of it, having statements in standard order with standard abbreviations of its terms.
schema
The _________ of a syllogism
is a three-letter description of the types of categorical statements it contains when arranged in standard order
mood
The __________ of a syllogism
is the number from 1 to 4
identifying the placement of its middle term
figure
A syllogism is __________
if and only if
the premises imply the conclusion
valid
A _______________ to a syllogism
is a syllogism of the same form as the original,
but with obviously true premises
and an obviously false conclusion,
in order to show the original to be invalid.
counterexample
What is a distributed term?
A term that refers to all members of its category
What term is distributed in the following statements: All S are P
No S are P
Some S are P
Some S are not P
All S are P - S is distributed
No S are P - Both S and P
Some S are P - Both are undistributed
Some S are not P - P is distributed
What are the 5 rules for testing the validity of syllogisms?
- Middle term distributed in at least one premise.
- Distributed in conclusion**, then distributed in **premise.
- Cannot have two negative premises.
- Cannot have a negative premise and affirmative conclusion.
- Cannot have two** **affirmative** premises and a **negative conclusion.
What is the Fallacy of the Undistributed Middle?
When the middle term is undistributed in both premises, then no necessary connection is being made between the premises.
What is the Fallacy of an Illicit Major?
If the major term** is **distributed** in the **conclusion**, but **not** in the **premise.
What is the Fallacy of the Illicit Minor?
If the minor term** is **distributed** in the **conclusion**, but **not in the premise.
What is the Fallacy of Two Negative Premises?
Any syllogism that has only E** or **O** statements as **premises.
What is the Fallacy of Two Affirmative Premises and a Negative Conclusion?
One premise** has to be **negative** if you have a **negative conclusion.