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Post by xxxxxxxxx on Mar 18, 2020 19:33:54 GMT
1) (-P --> -P)
2) (-P --> -P) --> P
3) (P --> P)
4) ((P -->P) --> Q)
5) (P --> (-P) <--> Q)
5a) (-P --> -P)
6) (Q --> Q) --> R
7) (Q --> (-Q) <--> R)
7a) (-Q --> -Q)
8) -P --> P --> Q --> R
.................--> -P --> P
...........................--> -Q --> Q
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Post by jonbain on Mar 18, 2020 20:35:33 GMT
crap
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Post by xxxxxxxxx on Mar 18, 2020 21:00:54 GMT
Good then point out which step is out of place. |
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Post by Eugene 2.0 on Mar 23, 2020 20:45:23 GMT
premises are indeed kinda strange:
3) (p --> p)
4) ((p --> p) --> q)
(3) & (4) - really?
3`) ~(p --> p)
4`) ~(p --> p) v q
4a`) ((p --> p) --> q)
5) (p --> (~p)) <--> q) -?
5a) (~p --> ~p) -? it's just the first premise.
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Post by xxxxxxxxx on Mar 23, 2020 22:10:02 GMT
premises are indeed kinda strange: 3) (p --> p) 4) ((p --> p) --> q) Q is a tautology of P. P as subject to the law of identity is self referential. (P --> Q) as subject to the law of identity can be expressed as ((P-->P)-->Q) or
((P-->P)-->(Q-->Q)).(3) & (4) - really? 3`) ~(p --> p) 4`) ~(p --> p) v q 4a`) ((p --> p) --> q) 5) (p --> (~p)) <--> q) -? 5a) (~p --> ~p) -? it's just the first premise. (-P --> -P) as subject to the law of identity is P also directed towards itself into a self negation into a new tautology. To say (-P --> -P), where -P is self referencing is to simultaneously state a self referentiality as -(-P).
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