Autosave: 2022-12-23 15:30:07
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					@ -37,6 +37,7 @@ Cannot be consistently denied as there is no possibility of it being false. It i
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## Formal definition
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					## Formal definition
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> A proposition P is truth-functionally indeterminate if and only if it is neither truth-functionally true or truth-functionally false.
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					> A proposition P is truth-functionally indeterminate if and only if it is neither truth-functionally true or truth-functionally false.
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					> should be avoided in arguments, they 'prove' everything whi
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```
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					```
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P
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					P
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					@ -34,6 +34,6 @@ From this we can derive the following property of logical possibility:
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## Logical necessity
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					## Logical necessity
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A sentence is _logically necessary_ if it is true in every logically possible circumstance which is to say: true on every possible truth functional assignment. Necessity and [logical truth](/Logic/General_concepts/Logical_truth_and_falsity.md#logical-truth) are therefore synonyms: anything that is logically true (a tautology) is true by necessity (could not be otherwise.)
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					A proposition is _logically necessary_ if it is true in every logically possible circumstance which is to say: true on every possible truth functional assignment. Necessity and [logical truth](/Logic/General_concepts/Logical_truth_and_falsity.md#logical-truth) are therefore synonyms: anything that is logically true (a tautology) is true by necessity (could not be otherwise.)
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Further, every logical truth is logically possible but not everything that is logically possible is logically true. It is possible that it is raining but this is not logically necessary - it could be otherwise, i.e not raining. However it is not possible that it could be both raining and not raining.
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					Further, every logical truth is logically possible but not everything that is logically possible is logically true. It is possible that it is raining but this is not logically necessary - it could be otherwise, i.e not raining. However it is not possible that it could be both raining and not raining.
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					@ -23,12 +23,12 @@ $$ \{ P \leftrightarrow Q, P \lor Q, P \land Q \} $$
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| F   | T   | F                     | T          |
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					| F   | T   | F                     | T          |
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| F   | F   | T                     | F          |
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					| F   | F   | T                     | F          |
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| $P$ | $Q$ | $(P \leftrightarrow Q) \land (P \lor Q)) \leftrightarrow (P \lor Q)$ |
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					| $P$ | $Q$ | $(P \leftrightarrow Q) \land (P \lor Q)) \leftrightarrow (P \land Q)$ |
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| --- | --- | -------------------------------------------------------------------- |
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					| --- | --- | --------------------------------------------------------------------- |
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| T   | T   | T                                                                    |
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					| T   | T   | T                                                                     |
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| T   | F   | T                                                                    |
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					| T   | F   | T                                                                     |
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| F   | T   | T                                                                    |
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					| F   | T   | T                                                                     |
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| F   | F   | T                                                                    |
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					| F   | F   | T                                                                     |
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We see above that the main connective, the material conditional returns true for every truth-functional assignment. In other words it is logically true. Consequently the argument is valid
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					We see above that the main connective, the material conditional returns true for every truth-functional assignment. In other words it is logically true. Consequently the argument is valid
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