Thank you for clarifying your argument. This is not what INTP had argued heretofore. Saying that a thing exists and that a thing is synonymous with "truth" are two very separate arguments. Please don't use an ambiguous concept like "common sense" to justify a lack of clarity on one's own part.
You argue that emotions "exist". Very well. As emotions have no physical existence, you are using a very idiosyncratic definition of the term which, I would argue, is so vague as to be useless in reasonable consideration and discussion.
This discussion has become increasingly pointless.
The conversation so far:
INTP:A
Mycroft: B is wrong
RH: I think he meant A, not B
INTP: I meant A, not B
Mycroft: Well, I agree with A but B is still wrong
RH: Nobody ever claimed B. Listen carefully
Mycroft: Okay, but you use fuzzy language and your definitions differ from mine
As for your complaints:
1. The difference between claiming the existence of something and claiming that something is true. I never said existing and being true where the same thing. You misunderstood me once again. But you seemed to reject not only the ficticious claim (the one nobody ever made) that feelings equaled truth but also the possibility that emotions could have any possible validity or relevance at all. Emotions have no physical existence, they are the name we give to a cluster of biochemical processes that CAN be messured and observed, as you yourself said. If you want to play the materialist card, sure, then there are not only no emotions but no thoughts or ideas either, then there is no reason and no logic, since those are all abstract concepts, software played on your brain which is nothing but a mass of cells with some electrical currents running through it. If you do allow for the use of abstract concepts, emotions are just another collective, abtract name for a process, a reaction. If you accept that Paris not only exists (is it a conglomeration of buildings - which are just our way of joining mass into units - or does the name also include all the coonotations that go with it, its inhabitants, its history, its culture, the seat of French government, etc?) but is the capital of France (meaning that Paris has a certain abtract function in some other abstract concept called a nation state) I see no reason why you shouldn't accept it as equally true when I say "Joe is angry" instead of saying "Joe's adrenaline level have drastically risen, his muscles have become more tense, etc.).
2. I don't have to justify any lack of clarity on my part. I am not in court. I am participating in a leissurly conversation using the everyday meaning of common words. This is the first time in 31 years anybody complains about my supposed usage of fuzzy language. I am usually known as a pedant and somebody very well able of clearly describing complex ideas. When I appealed to your common sense I was implying that you might want to consider context when reading people's posts and use Occam's razor to figure out what they might have meant if that isn't clear to you. People do that all the time. It is ambiguous, it is fuzzy, but it is how life works and an important skill if you don't want to die alone in a cave with all the rest of the tribe thinking you are a socially handicapped robot who takes everything literally, misreads people on purpose to challenge them just for fun and can't read between the lines. Just saying
3. You are arguing that something that doesn't physically exist, even if it can indirectly be observed on a physical level, does not "exist" in the usual sense of that word. That I use the word in an idiosyncratic manner. I strongly disagree with that...see point #1.
4. I also strongly disagree with your assumption that this usage of the term existence is so vague it is useless. It is indeed the common usage of the term. "The are/exist three houses on the hill" -> houses don't exist, they are just clusters of building material "Between those two brothers there is/exists no love" -> sort of self-explanatory, since you already mentioned the physical nonexistence of love "There exist six time zones between city A and city B" -> once again an abstractum.
Unless you are indeed a strong materialist who refuses to even temporarily accept the "existence" of anything non-material, of all forms of abstracta, we should actually be in agreement here. This is a case of miscommunication on both sides. As for the difference between existence and truth, well nobody claimed that it was the same thing, I just contradicted what seemed like a complete dismissal of emotions on your side. It was a reaction to your post, nothing more.
Tell me how you define truth and we can continue from there.
A statement can be true. Joe is sad is a statement. It can be true or false and there is a way of observing and finding out if it is true or false. In that sense emotions can be "true", which is what INTP was saying all along.
An object (abstract or concrete) can't be true. This piece of cheese is neither true nor false. Only my claim that the object in my hand is a piece of cheese can be true or false (assuming that we can agree on a definition of what cheese is). Democracy (to use a complex abstract example) is neither true nor false, only statements about it can be true or false. In that sense of course emotions can be neither true nor false.