1) No they don't, or learning a new language would merely be a matter of learning new sets of words to substitute for current ones in a one-to-one relationship. Beleive me, I do have some clue what I'm talking about. 2) Your point does not stand at all, it is precisely what is under contest. D'uh.
I will admit that I am no expert on this, but this does not exactly require a linguistics degree to understand.

The meaning of a word is determined only in its context, including, but not limited to, its grammatical context, emotive context, topical context, and extra-linguistic context(s). To speak of them as discrete in the sense you intend is higly misleading, since in any particular contextual situation, the word's "meaning" is being instantised in a way that can never be precisely reproduced in any other situation, ever.
Why so? I say that the meaning can indeed be precisely reproduced in any situation, because if it was not so, then words would be totally useless, since each one could mean anything. The fact that we are using words to represent ideas right now and the other guy is able to interpret the words reasonably well means that this is probably not the case.
You cannot enumerate the meaning/s of a word, for every time a word is used, it acquires a new shade of meaning.
So...how do you think that dictionaries are compiled?

2) A real number is an exact, unchanging quantity. How can a real number represent an amorphous range? (Indeed, "range" itself is only a metaphor in discussing this topic, for there is no set of dimensions in linguistic meaning.)
um...maybe using a function that returns the intensity? If there is no set of dimensions in linguistic meaning, then linguistic meaning would not exist as an objective quantity, so what you are trying to say is that languages are meaningless? That may be so, but at the moment I don't think we have any better way of symbolizing ideas.
As contexts intersect and linguistic situations emerge, certain linguistic expressions are called into play. The precise meaning at that intersection is determined by the intersection, and the expressions used are assigned their meanings by the intersecting contexts. At the intersection points, language brings into use such expressions as can be made to fit the context/s, not the other way around. Thus, a word does not have "10 or so" precise meanings, or even an infinite number of meanings, because the meanings are not, strictly speaking, properties of the words at all. (In case you're wondering, I assume no credit for this brief account, since I am lifting it directly from current linguisitic theory.)
You see though, when you say that "they are not properties of the word at all," you are also saying that all words mean the same thing, namely, anything. The very fact that meanings exist when put into context, or combinations of words, directly implies that parts of the meanings exist in those words. Otherwise, what would be the point of language in the first place? Every sentence would have its own unique word.

If you like, you can of course use "contexts" in place of "words" (just assign a number to every context), but it will amount to the same thing in the end.
Of course it works. Logical semantics is conducted precisely on the premise of finding out exactly what the meaning assigned to a particular expression was in a given situation.
And if the meaning assigned to a particular expression exists, the meaning is still fixed. Change the meanings given by words to those of expressions, contexts, paragraphs, or whatever else if you want, but the meanings would still remain fixed for a language to exist in the first place.
Actually, no. That they are called "languages" reflects upon the fact that they were christened by computer programmers, who, being normal human beings, were using metaphor as an intrinsic part of the language. Computer "languages" do not meet the criteria for language, and might more properly be called something like "mathematical function execution sets."
In other words, languages.

If this merely a metaphor, what is the meaning of the original word? And what are these "criteria for language?" A language is basically just a set of symbols (along with usage and transformation rules) for the representation of abstract ideas. Anything that can represent ideas symbolically would qualify, even a "mathematical function execution set.".
Really? So use those functions (I'll not even raise a fuss right now about differentiation between logic and mathamatics) to explain the meaning of "under" in the sentence "I studied under David Stewart," in comparision to the meaning of "under" in "Ivan worked under atrocious pressure."
These are pretty much the same core functions used by most programming languages out there, and it is certainly possible to program the meanings of either statement into a computer. Both sentences can be restated into something more definite for our purposes here. The first is essentially "I studied and Stewart was my teacher during this," if that is what it's supposed to mean. (it could mean a bunch of other things, too) The second can also be several things, but these two seemed likely to me: "Ivan worked while a physical force was acting on a part of him" or "Ivan worked while his brain was in a state of stress." We thus have at least two meanings of "under," and there are of course many more; they can all be grouped together by at least one certain classification system (the word under) and likely many more, but the important thing is
any one of them will work. Therefore, we can change "under" definition number X to a number of other words without changing the meaning. Since each definition has its own unique set of meanings (with a specified context), they can be so partitioned.
Also, math can be considered a subset of logic if the axioms of arithmetic and iteration are assumed, which was done there.
Antonymity is not the same as mathematical negativity, any more that synonymity is the same as mathematical equivalency.
Yes it is, along with a number of other meanings that can also be reduced to positive/negative statements of sorts, but that does not rule out this one. Furthermore, any one of the concepts can likely be used to represent all of the other things. None alone qualify as an elementary base - they all do - but any can be used as such. And of course, if you want to be purposely ambiguous, so that things only make sense in "context," you could just have everything attached to the same symbol anyway.
Such as description of the situation is a gross caricature. Let's assume one particular meaning of the word "nice" to be in effect for the moment, to which "mean" is the antonym. The relationship between the words is not binary, but more akin to analogue. The actual quality of the person in question is whatever it is (at that moment), and lets say that in can even be fitted somewhere onto the greyscale between the polar opposites of nice and mean. How a particular person might describe the individual in question is dependent entirely on their evaluative perspective. Nestorian Christians living in Persia described Hulaku Khan as magnanimous, wise, and of marvellously high character (and by the standards of the day, it seems he was), whereas we today would doubtless describe him as cruel. Where nice ends and mean begins is not set in any way, but a matter of contextual perspective.
What is your point? You keep restricting this to individual words, but those are of little importance here; the ideas carried by them is what we are concerned with. The fact remains that it
can be set so. (actually, it
must be set so even today for the language to mean anything) If you like, the "contextual perspectives" can be broken down instead of the words, but the fact remains that the meanings still exist for the reason given above. Axioms are decided upon so that the results will be the same, and even in language, such a system exists (it may be complicated, but that doesn't mean much).
Person C might describe B in quite a different way than A, even at the same time, if her context of speaking was different.
In that case, they are not saying the same thing, and we can thus seperate the meanings.
I'm afraid the devil is in the details, and he is a very malevolent devil indeed. As has been said, the meaning assigned to a word by the larger web of context/s is a function of the context/s. As an embodiment of the context/s, the word does not have a precise meaning to be stated.
Okay, replace "word" with "context," and there you go; you still have a system of partitioning.

As said above, modern linguistics points out how meaning is not a property of words, but rather that the words are embodiments of meaning.
That is exactly the same thing as a property of words.

The properties are only readily apparent in groups, but the elements
do have properties, or the whole would have no properties either.
Linguistic expressions have their usefulness precisely because of their flexibility, because of the ambiguity you wish to remove. The idea that one could discretely digitise this is just plain funny. What happens when the 102nd person enters the room and we have to describe his level of niceness? Then we suddenly find that our 101 levels of niceness do not correspond to the reality we are trying so desperately to pin down. Perhaps if we expand it from a mere 0-100 to a range of values sufficient to accomodate every person who has ever or will ever live? Well, firstly the quantity is unknown, so it would be imposssible to know where to position people, and secondly the niceness of a person is not a simple value: a person might be nice in one way, not at all in another, and somewhat nice in a third, and so on. So how are we to classify him on our grand scale? Beyond this, what if I wasn't talking about nice as a quality of people, but of nice as a property of interior design, or of food, or of a situational development? The antonym in each case is something quite different, making your zero pole of the digital scale correspond to entirely different things in each case. Not exactly precise, is that?
No no; when I said 1-100, I meant a continuum in that interval. Since "niceness," as you said, needs at least one more element, we can further break it down into a number of other words. We classify the person by the same methods I gave earlier: see how the person responds to various precise actions. Based on the response, it can be determined how "nice" the person is in some given sense, or an average, or whatever else. Such distinctions must exist, no matter how subtle they may be, or, as I said earlier, words (and heck, all language) would be absolutely meaningless, since anything would mean anything else. If this cannot be done (which is quite possible), that means that the concept of "nice" (under any context) is relative and therefore nonsensical.
But beyond these niggling, though very telling problems with your system, the whole premise upon which it is constructed is faulty. This (flawed) attempt to quantify "nice" exists only by overlooking the fundamental need to demostrate how "nice" can be given quantitative values in the first place. It is the same sort of problem that undermines utilitarian ethics: how do you measure goodness, happiness, rightness, or in our case, niceness? Where is the 50% mark?
Very simple: it is arbitrarily
defined to be somewhere. It does not matter where, so long as there is a relative point from where everything else can be gauged. The very fact that an idea exists means that it
must be quantitative. All quantities are qualititative and all qualities are quantitative; either property can be used to represent ideas.
Sarcasm is the employment of words by language such that the apparent meaning being embodied by them is at odds with the actual meaning. Sarcasm exists precisely in the incongruity between stated and actual meaning. Adding a symbol to indicate sarcasm would be precisely a statement, and thus would in that moment cease to be sarcasm. "I am SO happy," would become merely "I am not so happy." The sarcastic element is destroyed by any attempt to state it.
That seeming incongruity is
exactly the symbol that indicates sarcasm, and it is no less a symbol than an explicit marking somewhere would be. All aspects of language are such symbols.