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15 Cards in this Set
- Front
- Back
Truth-Functional Statement
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Consists of two distinct simple statements, which are connected by and (a logical operator) and each simple statement has a truth value ( is either true or false)
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Logical Operator
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Words like "and" "not" "or" "if...then"
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Dot ( . )
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Means "and" and it's logical function is that it's a conjuction.
Ex: Q . P if the . means that both P and Q need to be true for the whole thing thing to be TRUE |
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Tilde (~)
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Not - it automatically negates the truth value of the phrase. to negate the truth value of a complex sentence just put the not in front of the complex statement.
Ex: It is NOT the case that... |
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Wedge (v)
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Stands for "or"
or statements can be either inclusive (one part doesnt count on the other - meaning both can be true), or it can be exclusive (meaning both can't be true) For P v Q it is only false when both are false. |
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Conjunction ( . )
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and, but, while, however, also, moreover, although, yet, whereas
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Negation (~)
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not, it is not the case that, it is false that, it is not true that
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Disjunction (v)
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or, either....or, unless, otherwise
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Conditional (Horseshoe)
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P, then Q
The part that comes after "if" is called the antecendent and the part that follows the "then" is that consequent. The ONLY time a conditional statement is false is when P is true and Q is false. it is true all other times. Every time P then Q Each time p then Q All cases where P, then Q In the event of P, then Q On condition that P, then Q Given that P, then Q Provided that p, then Q In any case where P, then Q Supposing that P, Then Q On any occurence that P, then Q For every instance of P, then Q |
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If and only if
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Whatever follows IF is the antecendent (P)
Whatever follows ONLY IF is the consequent (Q) |
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Main logical operator
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the logical statement that determines the final truth value of the statement. Parentheses are an example.
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Contingent Statments
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statements that could be possibly true or possibly false
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Logically equivalent statements
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when two truth functional statements appear to be different but have the same truth table
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Contradictory Statements
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two statements that have opposite truth values on every line of their respective truth tables
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Consistent/inconsistent statements
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Consistent: there is at lease one line on their respective truth tables where both are true
Inconsistent: there is not even one line on their respective truth tables where both are true |