Aristotle's "is" "was" asymmetrical (in his time); it "means" "is [in] a [category] ..." and can only properly be understood in terms of the container metaphor on which it is based. (Lakoff)

The ravages of time have "devolved" the general understanding of the predicate form from [is a](object,category) to [is](object,object), a special case of the more general three place [expression](object,relation,object), namely [identity](object,"is",object) (but not among philosophers and mathematicians).

Understanding ancient philosophy includes grasping and remaining consistent with the paradigm of the period. We discuss the Newtonian-Relativity paradigm shift. (Kuhn) Similar changes apply to the evolution of language.

Only if one "understands" "is" as only "meaning" "identical" or "same" does it preclude asymmetry.

Thomas,

Socrates is a man. ("is" of class inclusion)
Men are mortal. ("is" of predication)
Socrates is mortal. ("is" of predication)

These are predications that are asymmetrical.

See my previous post.

Many more things than Socrates and men are mortal. We cannot conclude that something is mortal entails that something is Socrates or that something is a man.

Carrot tops are green.
Grass is green.
If X is green then X is a carrot top. (False)

A relation R is symetric if for all a and b R(a,b) = R(b,a).

Predicated on (man, mortal) is not the same as Predicated on (mortal, man), because man is not an adjective and mortal is not a noun (in this context).

Predicated of (noun [subject],adjective [predicate]).
"Predicated of (adjective [prediace],noun [subjec]). Is not correct syntax and not well formed, and not what Aristotle meant.

Thomas,
Please explain why you choose to say "grass is NOT green" in the context of a discussion of the form of predication when the "subject, is, predicate adjective" FORM is simply being illustrated? You seem to be responding to the sentence is a purely semantic fashion - completely ignoring the syntaxtic structure.

The logic of predication is asymmetric. If you are totally convinced otherwise, you will be going against thousands of years of time-binding.

In Aristotle's time the sense of "is" (of predication) should be construed as "... shall be described as a member of catogory ..."

Some people today have an idea fixe that "is" always means "identical to".

Another "novice" general semantics view that I have seen, claims that "is" can only be used if the totality of characteristics is included on both sydes, and is denied by "you can't say all about anything".

Bob Pula used to illustrate this at seminars by drawing a big "cloud" with lots of things in it and putting "is" and writing one thing from within the cloud.

The is of predication can be seen as abstracting a property or characteristic from the many characteristics of the subject.

Grass "is" green can be understood as meaning one can abstract a characteristic that we call the color green from an observation of some grasses.

Logic makes "grass" an abstract subject, and "green" a property that identifies the class that the speaker whishes to talk about.

If you are training a new time-binder, you take the toddler out, point at some stuff that he can touch, and assert "Grass is green". You pick out some other things and say "this is green too". Then, after several iterations you get the toddler saying "green" in the "appropriate" time-binding context.

Here are some possible formulation changes and paraphrases we might adopt in general semantics.

Is of identity. Use "is". (identical, same as, equal). Example "One plus one is two." Not recommended for use except in rare case.
Is of class inclusion. Use "isa". (in the class or category of). Example "John isa person." Recommend to include "etc." "John isa person, etc."
Is of prediccation. "Use "exhibits". (shows the property or characterists). Example "Grass exhibits green." Recommend to include "etc." "Grass exhibits green, etc."
Is of existence Use "exists", Example "I think, therefore I exist."

David,
I don't think "class of things that appear green" would avoid predication; how would you get the class in the first place?

Thomas wrote I should tell you that I consider 'logic' to be pretty well a waste of time in any event, all the 'logic' we need is in mathematics.

Curious that you should think this way. Without "logic" mathematics itself would be impossible except for a few trivial operations. Logic provides and validates the rules of inference used in mathematical proofs, without which we could not prove theorems. It is the basis of "sane" reasoning (reasoning with valid inferences only). Popper's falsification principle depends upon and uses the basic logic rule of inference known as modus tolens. While mathematics may include some ideas in addition to logic, it is wholly dependent upon logic for its validity.

Logic provides validity. One cannot achieve validity without the rules of inference provided by logic.

You consider logic a waste of time.

And validity, that is also a waste of (your) time?

Who has tried the approach that I illustrated, and who has tried Nora's approach to child rearing?
When we parents teach a child, in my experience, we use the fewest words in sentences; this establishes neurological distinctions with fewer repetitions. The earliest form does not even use predication syntax or "qualified" predication syntax; the earliest form is usually repitition of a single word (as I recall from my children's earliest days). Let's hear from those who have actually raised children. Anyone tried these speculative approaches consistently from birth? (Other than Piaget?)