Chapter 9 & 9.1 Flashcards
Consider the following argument:
If there is a recession this year or a foreign affairs fiasco, then the president will not be reelected .
There will be a recession.
___________________________
The president will not be reelected
This is what type of argument?
Deductive
In the deductive argument about the president and their reelection: the antecedent is the _______ proposition p or q, and the second premise affirms p, not the disjunction as a whole. Thus this is a combination of what two types of non-categorical syllogisms?
disjunctive; a combination of both disjunctive and hypothetical syllogisms
_________ logic is one main branch of what is known as symbolic logic.
Propositional
Propositional logic is a branch of what type of logic?
Symbolic
In modern ______ logic, words like “all,” “some,” “if … then ,” and “or” are replaced with symbols.
Symbolic
Propositional logic is the logic of _____ statements - statements that are made up of other, simpler propositions.
Compound
Here are some examples _______ statements:
1. My sister is happy, and she’s throwing a party.
2. My brother is not coming to the party.
3. The Democrats will win or the Republicans will win.
4. If the Democrats win, then my sister will be happy.
5. The party will be fun if and only if Buzz shows up.
Each of these statements has one or more component statements with an italicized expression, called a connective , which tells us how the components are related
Compound
In symbolic logic, a _______ proposition, or statement, is called a conditional statement.
Hypothetical, because of its dependence on the events taking place in the premise
In the state statement “The party will be fun if and only if Aaron shows up,” the connective “if and only if “ is called a ________.
biconditional
A ______ is a way of expressing two component statements, called _____ , in a single statement .
For example:
6. The rent is due, and I have no money.
conjunction | conjuncts
Consider the following statement:
The rent is due, and I have no money.
For it to be true, both ______ must be true. And if they are both true, the _____ is true.
conjuncts | conjunction
The conjunction sign ____ represents the relationship
between the truth of components and the truth of a compound statement as a whole.
• (called the “dot”)
The logical form of a conjunction is…
p • q
The letters “p” and “q” stand for the two component statements, and each of those components can be either true or false. The truth or falsity of any statement is
called its ____, represented by T and F.
truth value
The statement
“Lemons are fruit” has the _____ value of T
While the statement
“Lemons grow in the Arctic” has the ____ value F.
truth value
Consider the following statements:
- Renee and Tom took logic.
- Tony and Sue got married.
Statement 10 is a normal conjunction: It is shorthand for “Renee took logic and Tom took logic.” But 11 is different. Why?
It does not mean merely that Tony got married (to
someone) and chat Sue also got married (to someone). It means that Tony and Sue got married to each other.
So the sentence makes a single statement about a pair of people; it is not a pair of statements that can be joined by conjunction or represented by the truth table for the dot.
When discussing negation we represent the denial of a proposition by what sign?
the negation sign called the “tilde” or represented by “ ~ “ symbol
T and ~T are contradictory propositions, meaning….
they cannot both be true, and they cannot both be false.
T and ~T are ______ propositions, meaning they cannot both be true, and they cannot both be false.
contradictory propositions
In the following statement what would be the symbolic representation of the double negative?
It’s not the case that Larry will not come.
~~L
which essentially means Larry will come. Negation is an on / off switch; flip it twice and you ‘re back where you started.
A _____ statement asserts that either p or q is true.
disjunctive
disjunctive statement (in symbolic logic)
asserts that either p or q is true (so at least one component must be true, or can also mean both)
in a disjunctive statement, p and q are called the disjuncts, and the connective “or” is represented by what symbol?
V
the “vee” or “wedge” sign
in symbolic logic the connective “___” is represented by V (the “vee” or “wedge” sign).
“or”
What is the symbolic form of the following disjunctive statement:
We will grow corn in our field or we will let it lie fallow.
G V L