'Ere yer go:
wleg wrote:Unfortunately, Aristotle never understood how the subject and predicate are related to the "existence" of each other to construct knowledge.
Nor do I. What is "existence" in quotation marks and how is it different from existence without quotation marks? You have said:
wleg wrote: DEFINITION OF EXISTENCE: “The existence of a thing is a construct of its attributes.”
You cannot build knowledge of the sort you appear to desire on such a foundation, because if true, it means that attributes are constructs of their attributes, which are constructs of their attributes and so on ad infinitum. By that definition, attributes don't exist; in other words, there is nothing that you can base knowledge on.
wleg wrote:Philosophers have never constructed a comprehensive definition of "knowledge" grounded on understanding the nature of the “existence” that subjects and predicates have to each other.
Probably, because they have been too busy trying to construct an understanding of existence grounded on the relationship that subjects and predicates have to each other.
wleg wrote:Why else could so much confusion and contradiction still exist about the nature of "knowledge" after twenty-five centuries?
It isn't confusion, it's disagreement. People think differently. As Ginkgo pointed out a while back, there are rationalists and empiricists. It might help you to think of mathematicians and physicists.
Mathematicians manipulate symbols in such a way that proves things about relationships between symbols.
Physicists know things because they can measure them.
Amongst philosophers, there are some who think you can apply the sort of reasoning used by mathematicians to concepts and arrive at proof. They are the rationalists. Among them are philosophers keen to use reason to prove the existence of god using some brand of ontological argument, the latest edition of Philosophy Now is crawling with them.
Then there are philosophers who think that the only way to arrive at knowledge of the real world is to look at it. They are the empiricists.
Philosophy and science are graveyards for ideas about the world based on rationalism. The advantage to empiricism is that it doesn't commit it's adherents to any belief that might be demolished by observations; the downside is that you have to accept that you don't know anything.
wleg wrote:The only possible reason is the failure of Aristotle and all the other philosophers to construct a comprehensive definition of “existence” to know how “knowledge” is constructed.
I'm sure, given time, you could think of other reasons. Anyway; one feature of empiricism is that knowledge does not depend on a definition of existence. As Berkeley showed, the nature of existence is irrelevant. The only thing we know is that phenomena exist. Any hypothesis that claims to account for the phenomena is metaphysics, including the belief that there is a real world that corresponds to those phenomena. It could be that the world we experience is a bunch of ideas in the mind of Berkeley's god, it could the deceptions of Descartes' evil daemon, it could be Susskind's holographic projection from the edge of the universe, it could be a dream. None of those hypotheses make the slightest difference to what we perceive. As Kant pointed out, you know the phenomenon, you don't know the noumenon.
wleg wrote:Will you answer this simple question: How is it possible to construct philosophical knowledge of “knowledge” itself without first understanding the nature of “existence” itself?
16 years of corresponding on philosophy forums should have taught you that it is not a simple question; it is loaded with your assumptions and interpretations. Still: a mathematician knows that 2+2=4 and while I accept that some people dispute even this, it's truth value is independent of existence. 2 oranges and 2 oranges makes 4 oranges whether or not oranges exist. By contrast, a physicist can count his oranges and know how many they have. A philosopher can pick one or other type of knowledge, or try for some Kantian synthesis, but at the end of the day, the nature of existence is nothing to do with knowing.