Correction: (max 500 charact.)
The complaint will not be published.
I 48
Extensionality: "Law of extensionality": if the sentences S1 and S2 have the same truth value, then, each composite sentence that differs only in that it has S1 as a subset , where the other has S2 as a subset, also the same truth value.
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Truth values , >
Truth , >
Extensions , >
Clauses .
PriorVs: one can count mixed constructions like "__is green and__" also "__believes that__" into the same category as the simple. - If the law of extensionality is true, then must "grass is pink" and "grass is purple" be the same thought.
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Thoughts , >
Thought/Frege , cf. >
Fregean meaning , >
Fregean sense .
Solution: "x thinks, grass is pink" is not a compound sentence with "grass is pink" as a component.
Cf. >
Compositionality , >
Thinking , >
Sentences , >
Propositions .
I 50
Extensionality/Prior: Lesniewski/Lukasiewicz: if one drops the E, one must admit that some propositions are neither true nor false.
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St. Lesniewski , >
J. Lukasiewicz .
PriorVsExtensionality: truth value of a statement depends not only on its truth value. (Circular).
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Circular reasoning .
I 93
Law of extensionality: propositions with the same truth value are identical.
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Identity , cf. >
Equivalence .
I 139
Extensionality/Prior: "cause", "bring about" seems to be the most extensional operator: the one who brings p about, brings everything into existence ipso facto, what is equivalent with p.
Cf. >
Command/Prior .
But it does not bring into existence what it contains (entailment, asymmetric implication ): E.g. someone is caught by the FBI and a communist, but that does not bring about, that he is a communist.
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Causation , >
Entailment/Prior .