🚀 go-pugleaf

In article <1992Oct30.172420.1@eagle.wesleyan.edu> skumar@eagle.wesleyan.edu writes:
>Please correct me if I am wrong but I think that if I found a creature which
>was like a crow in all respects but it was white in color, I would call it an
>albino crow or something. I would not call it just "a crow". Does this not mean
>that we accept "all crows are black" by definition so we need not prove it?
>

In England, there are some piebald crows, that is crows that are
black and white. They have a special name. They are called magpies.
They have become more common in recent years, probably because they
were made a protected species.

I missed the start of this thread, but wonder if the the problem
that people are having with

All crows are not black

is along the lines of

All that glitters is not gold

where the "All" is, in fact, a peculiar idiom of the English language
that means "Some", but with an emphasis of a kind.

The book from which I have been learning logic, namely Teach Yourself
Logic, warns that All ... not ... of this kind needs to be expressed as

No ... ...

in order to avoid this idiom.

Thus, All crows are not black, in the idiomatic form is really

Some crows are not black

Whilst, All crows are not black, in the literal sense of the words is really

No crows are black



I have found the study of Logic fascinating, but still have a long way
to go. I note that it was a compulsary subject in the Medieval Universities.
I believe that it should become a compulsary subject again, starting in
schools and continuing in everyday usage, much as other basic skills such
as reading, writing, spelling and mathematics.

----

Hubert was trying to do something but could not get the
duff equipment to work. Hubert asked for better equipment.
Hubert heard "A bad workman always blames his tools" said.
"Ah", responded Hubert quickly, "Your implied syllogism exhibits
the Fallacy of the Undistributed Middle".
"Now, may I please have some proper equipment?"