- ...variables,
-
Frege used the word `function' where we now use the word `relation'. This was again adopted by Hilbert and Ackermann in the second edition of their book (1938). Unfortunately we also use the words `function symbol' in modern logic, but with quite a different meaning, namely such will be interpreted as a function on a domain to itself.
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- ...geometry,
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In a letter to Hilbert at a later date he said there was no reason to prove the axioms of geometry consistent because they were true.
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- ...False
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Frege describes the truth value of 17#17 for each of the four possible truth values of P,Q. Thus we almost have the first
truth table;
but there is no table, just a verbal description.
Truth tables are usually attributed to Wittgenstein who was well versed in
Frege's work, and had gone to study with Russell at Frege's suggestion.
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- ...law
- In Frege's book it was written
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- ...have
- A slight variation on this applies to 33#33, namely one gets 34#34.
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