Re: Aristotelian syllogistic and monadic FOL

It was said:
"Aristotle assumes that
| all the class terms in a categorical argument denote
| nonempty classes.."
and
"The author plausibly argues that the "A" form, each X is Y,
is meant in a way that assumes there are some X's, although
see the caveat below..."
Is there any evidence for this in Aristoteles work ?
Did he say in a: each X is Y ---- or did he say: All X are Y ?
Or is this needed for First Order Logic- Praedicative-logic?

In term logic, and that's how i understand Aristoteles, one has terms
("horos") like Subjects, Praedicates and the Middle term shows, that a
praedicate of one categorical proposition is a subject in another
propostion, like unicorns, animals, or properties like being green.
Term logic has the distinction between "Umfangslogik" ---where terms
are "classes", "containers", "aggregations of elements, of aggregants,
de Morgan "On Syllogism" gives the example "man" --- and "Inhaltslogik"
- where one speaks of "properties, "compund of componenets",
"attributes", de Morgan gives the example "human".
Both have a calculus - one is like a picture in a mirror to the other.

I'm using now "Umfangslogik", so talking of "green things" in place of
"being green".
As described by others, there are four pairs of categorical
propositions, four of them are proposing existence, like i :Some S are
P. And four stating Non-existence, like a: All S are P.
Now one makes a list of different departments, only counting people
with computer-knowledge,universe of context,and grouping like this:
knowledge of windows only, knowledge of linux only, knowledge of both,
knowledge of neither.
Now take these four propositions: All windows-people are linux-people -
All windows people are not linux-people - All linux-people are
windows-people - All (with computer-knowledge) are linux- or
windows-people. With these, one doesn't get a contradiction, but well
the result, that in this department nobody is capable of handling a
computer.
After all, one can do this with Venn-Diagramms or with circuits, where
switches are interpreted as terms, and when the light is on with both
switches letting pass electricity, this is interpreted as " there are
people " (light on) in the area " linux-people and windows people" (
both switches on).
Is FOL not capable of expressing this ?
Hero

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