HOME TOP UP PREV NEXT 1 2 3 GERMAN MAP Tractatus Logico-Philosophicus 6.120
That "(x) . fx :: fa" is a tautology shows that fa follows from (x) . fx, etc. etc.
This sign, for example, would therefore present the
proposition p q. Now I will proceed to inquire
whether such a proposition as ~(p . ~p) (The Law of
Contradiction) is a tautology. The form "~" is written
in our notation
Hence the proposition ~(p . ~q) runs
thus :--
If here we put "p" instead of "q" and examine the combination of the outermost T and F with the innermost, it is seen that the truth of the whole proposition is co-ordinated with all the truth-combinations of its argument, its falsity with none of the truth-combinations.