Re: In need of the all-out revision of symbolic logic

On 4月30日, 午後10:54, Frederick Williams <"Frederick
Williams"@antispamhotmail.co.uk.invalid> wrote:
Eukie_M_SHIRAISHI wrote:

In the Fregean Theory of Logic (the standard theory of logic in the
20th century),
“p implies q” has had been defined to mean “not-p or q”.

Here let P be “A lion is a mammal” and Q be “A lion and a whale are
both mammals”
It is clear that Q implies P but P does not imply Q.
Hence “P implies Q” is a falsity.

Not so. Since Q is true, P implies Q.

Do you think that "A lion is a mammal" implies "A lion and a whale are
both mammalds " ?

"A lion and a whale are both mammalds " does imply "A lion is a
mammal"
but "A lion is a mammal" does NOT imply "A lion and a whale are both
mammalds "

We found that it is truly a grave mistake to define "p implies q" by
the truth-table.

See:-<http://www.age.ne.jp/x/eurms/PNG/Key/Honron-3.html#02-3>


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