If you can explain me why FlatAssembler wouldn't think that "yes" meant something like "boiling" in English, then I would accept that some of his etymologies are true.

Because there is absolutely no evidence to support that. (FlatAssembler has therefore also not suggested "yes" in English means "no" or "potatoes" or "spaceship".) Your objection is irrelevant.

Though I can't really see how you can call an etymology you don't even understand (like Colapis coming from *kwol-h2ep and meaning "a river with many meanders") plausible, ...

Browse through some etymologies in the Oxford English Dictionary, etymonline.com or Wiktionary. You will find this proposal is in line with various other accepted or proposed etymologies. It is indeed difficult to prove this is the correct possibility, but it is not anomalous. Again, your objection is irrelevant.

...especially since FlatAssembler admits to have no expertise in the field.

That's called an ad hominem argument and it is also irrelevant to the proposal. An expert can be wrong, and a novice can be correct. Ideas are correct or not independently of their creators. Regardless, FlatAssembler does clearly understand (and accept) the basics of historical reconstruction, sound change, etymology, etc. You clearly do not. Again, your objection is entirely irrelevant.

And what do you think is the difference between saying "'Yes' means 'boiling' in English, and it comes from PIE *yes." and saying "'Colapis' meant 'river with many meanders' in old Croatian and it comes from PIE *kwol-h2ep."?

About the same as the difference between claiming that a rhinoceros is a type of plant and actually study biology.

You're just posting nonsense now. Move along. (I suggest reading something about Historical Linguistics, maybe an intro textbook, if you have any sincere interest at all.)

You've said you taught classes on PIE.

To be clear, I have taught classes about Historical Linguistics. Not about PIE specifically (but of course it was discussed).

So, if there is a difference between those two statements (apart from one being obviously silly because of there being many people who would recognize that the conclusion is wrong), you should be able to explain it.

Saying something entirely absurd and asking me to argue against it is a waste of my time (and your time). There is no evidence for the silly position you gave. There is comparative evidence (sound change patterns and the meaning of related words in modern languages).

If you aren't, you should admit that FlatAssembler's methodology is fundamentally flawed and that you were wrong to affirm what he had said.

The methodology is fine. The details may be wrong (or right). If you'd like to learn about the methodology of historical linguistics, start here:
https://en.wikipedia.org/wiki/Sound_change
https://en.wikipedia.org/wiki/Comparative_method_(linguistics)

It is also unreasonable to expect me to explain all of this to you in this topic here rather than just letting FlatAssembler discuss the specific ideas. Usually when I teach these topics, it takes a whole semester. And I'm not going to try to summarize that for you here when your interest does not seem sincere (you will probably just remain "skeptical" anyway, which is fine, but means I'm wasting my time), and when you can just look it up online yourself for the basics or read a textbook for the details.

As a very basic explanation, compare German 'ich', Dutch 'ik', and English 'I'. These words all mean the same thing ("I", the first-person singular pronoun) in these related languages. We can assume then that an earlier word also meant that. But how was it pronounced? Probably more like the German or Dutch form, because it would be strange to randomly add a consonant at the end of a word rather than (the much more frequent process of) losing one at the end. So the original form was probably *ik (k rather than ch because k>ch is a more natural shift than ch>k). That is how it has been reconstructed for Proto-Germanic: http://www.etymonline.com/word/I
We can do the same thing, on a much larger scale, and with more complicated examples, and make some good guesses about PIE. Sound changes are regular (systematic-- look this up!) and allow us to have a good idea about the pronunciation of words in proto-languages. Meanings are harder to reconstruct, but based on the meaning of words in modern languages we can have at least some idea of the broad meaning of words.

I have reached the end of going back and forth about you not accepting the methodology of historical linguistics. You can believe whatever you want. But it's not going to be helpful to keep telling us you don't believe in the methodology of linguistics-- in that case, go do something else. Unless you have a better methodology, you have nothing to contribute. Move along.

Daniel, perhaps you know this, is it very unusual for a syllabic 'l' and 'il' to be freely interchangeable in a language?

I'm not sure, but that doesn't seem implausible to me given other evidence supporting it. Liquids (R, L) and vowels seem to mix or go through metathesis (switching places) fairly often, such as in the spellings theatre and table, which vary between syllabic final liquids and consonant+vowel (or vowel+consonant) clusters, depending on the particular language/dialect/time you look at.

/il/ in particular has a relatively distinctive vowel, and I might expect /a/ or schwa by default, but vowel shifts happen so often and in such extreme ways that could be explained secondarily. Or the location in the word could condition it such as being near a palatalized consonant (I'm not sure on the details for the languages you're describing at that point in time!).

The argument that the proponents of Illyrian being a satem language often use is the ancient name for Vrbas being Osseratis, persumably coming from PIE *h2egjer and meaning "lake". But isn't it coming from *h1en-ser-at and meaning "where (one river) flows into (the other)" just as a valid etymology?

It's a valid hypothesis until falsified. It's not a valid etymology until demonstrated to be more than just a hypothesis. (Careful on the wording there, that's all.)

It seems to me that those origins are distinct enough you should be able to differentiate between the hypotheses (falsify one) by looking at the details of known sound changes. It would be unexpected if both forms could really generate the same result. But I don't know enough about those details to tell you which one is right.

The science is too bookish and nerdy to understand, oh no!
...really?

You've stated elsewhere that you don't have a background in linguistics (not even enough to browse through threads here and understand them-- that's what you said), and you're now implying that because you can't follow a conversation that gets into technical details that someone who is objecting to the topic because they also don't understand is right? You realize how absurd that is, right?

Now, if you are sincere: this is not an "introductory" discussion to the topic and requires some substantial background knowledge. While everyone is welcome on the forum, that doesn't mean every question needs to be at the introductory level. If you'd like to know more about the basics, please start a new topic and I'll be happy to discuss that with you. Or read on Wikipedia, etc., if you prefer.

Going to a physics forum and saying "I don't understand quantum mechanics" is off-topic and irrelevant. Obviously they'll be talking about things you don't understand, and the same applies here. But, sincerely, if you also want to discuss introductory topics that's great, and you're welcome to do that here.

I just made an observation that his arguments make the most sense to a layman.

Why should that be important for a technical question? It would be like me walking into an advanced graduate course in biochemistry and giving my uninformed opinion after the lecture.
I didn't mean to respond too harshly, but without something more substantive in a response (as you have now written), how else should I reply?

FlatAssembler argues that:
A) The mainstream etymology of the Croatian toponyms is very flawed. His arguments make some sense.

The current proposals are somewhat weak in supporting evidence. (My early comments here to FlatAssembler warned that it will be hard to provide more compelling evidence for competing theories as well though!)

B) Many Croatian toponyms are explicable using an ancient language called PIE. Most of his arguments are not even comprehensible (to me, nor to LinguistSkeptic and apparently also not to Daniel).

Proto-Indo-European is not a fringe theory in any sense. It's been an accepted hypothesis that every linguist knows about, since the late 1700s. The details (like exactly where or when it was spoken) are up for debate, but its existence and some of its general properties are not. In fact, only fringe theories would deny that PIE existed!
https://en.wikipedia.org/wiki/Proto-Indo-European_language
Without knowing that, I can understand how this thread would read oddly. But that's the fault of history classes not teaching about PIE, not the fault of us talking about shared technical knowledge.
Read the quote below from William Jones in 1786-- https://en.wikipedia.org/wiki/William_Jones_(philologist)

    The Sanscrit language, whatever be its antiquity, is of a wonderful structure; more perfect than the Greek, more copious than the Latin, and more exquisitely refined than either, yet bearing to both of them a stronger affinity, both in the roots of verbs and the forms of grammar, than could possibly have been produced by accident; so strong indeed, that no philologer could examine them all three, without believing them to have sprung from some common source, which, perhaps, no longer exists; there is a similar reason, though not quite so forcible, for supposing that both the Gothic and the Celtic, though blended with a very different idiom, had the same origin with the Sanscrit; and the old Persian might be added to the same family.

All of that turned out to be correct, and is accepted in modern Linguistics.
---

C) PIE is, contrary to the mainstream linguistics, related to another ancient language, called PAN. Most of his arguments make no sense (for example, he supposes the the words like "ser" and "qalur" are related), but some do (like that "danu" and "danaw" are related).

1. Proto-Austronesian is another widely accepted hypothesis: https://en.wikipedia.org/wiki/Proto-Austronesian_language
2. However, there is NO widely accepted theory that PIE and PAN are directly related in any sense. That's implausible (how would people move between central Eurasia to/from Taiwan many thousands of years ago, before the invention of the wheel, etc.), and just not supported by any substantial evidence. The proposed related words are just coincidence. I told FlatAssembler this at the time (in contrast to LinguistSkeptic constantly repeating that I unquestioningly support everything FlatAssembler has said).
3. Regardless, a potential relationship between PIE and PAN is irrelevant to the rest of this discussion. That was a tangent.

A) FlatAssembler's etymologies are possibly true, but not much more likely than the mainstream Croatian etymology is. Daniel defends mainstream Croatian etymology with arguments that don't really make sense to a layman, nor to FlatAssembler. Nevertheless, he encourages FlatAssembler to continue his work.

I'm simply saying we don't have enough clear evidence to be able to make an informed decision about which proposal is correct. I don't know enough to decide between the two hypotheses. This is a data question, not a methodology question. The main warnings I gave FlatAssembler were about reading too much into little data and that there may be some coincidences. Yes, I did encourage the continued pursuit of these hypotheses (if that interests FlatAssembler, and it seems to), because maybe some clearer evidence will pop up. The best way to pursue them would be to find evidence against the other proposals, that can falsify those. I have no idea if such data exists, but if so, that is a strong argument that some other proposal (such as FlatAssembler's) should be taken seriously. I have also suggested FlatAssembler look into the norms of publication on topology because that isn't my area so I'm not sure what counts as 'sufficient evidence' to take a new proposal seriously. That allow some concrete goals to be set (or to know when continuing to pursue the question is no longer productive).

B) FlatAssembler's idea that PIE and PAN are related is implausible, and his arguments are fallacious. Daniel's counter-arguments don't really make sense to a layman either.

Correct, but as I said above, that was a tangent and not related to the main question here. I did point out that if data is being misinterpreted in that case, it's worth double-checking it in other cases though!
Simplified explanation of that: sometimes words in unrelated languages sound similar. For example, Japanese "namae" means "name", and it seems like those words could be related, but there is no historical/linguistic reason at all to believe they actually are. When languages actually are related, there are many more (and more systematic) similarities.

LinguistSkeptic argues that:
A) FlatAssembler's methodology is extremely flawed, and would lead to outright absurdities if applied to modern languages. His arguments are fairly convincing to a layman. FlatAssembler and Daniel claim that LinguistSkeptic has misunderstood what FlatAssembler was doing, but apparently don't bother too much to explain how.

To put it bluntly, LinguistSkeptic's apparent counter-argument are as uninformed and transparently irrelevant as a creationist's arguments against evolution. He might as well be saying "dinosaurs are still alive in Africa!".
I wouldn't be able to explain the entire theory of evolution here, nor everything about historical linguistics. Even if I tried, you would probably find it to be "technical for the layman", which is fair, and which is why I'm not trying to write a book here explaining the established methodologies of the field. But none of it is a secret. See these Wikipedia articles for example, which do a reasonable job of explaining it "to a layman":
https://en.wikipedia.org/wiki/Historical_linguistics
https://en.wikipedia.org/wiki/Linguistic_reconstruction
I have taught classes on exactly this, and would invite you to take one of them if that was practical. Other than that, I could recommend a textbook.

People who read this thread probably want to inform themselves about Croatian toponyms, and other things discussed here, and make some conclusions by themselves. So, why do you think people shouldn't choose the LinguistSkeptic's position?

Because from the beginning, this was not a teaching thread. This was a technical question about a proposed theory. That's like saying every scientific advance should be made with the needs of an introductory class in mind, in case any first year undergrads happen to be listening. Those are just two completely unrelated things, and this thread has never been meant to be accessible to someone without a background. There are dozens or hundreds of threads here that are. There's no reason we can't have both on a forum.

If there were two astrologers arguing about something about astrology, and there comes a skeptic who argues that the methods they use are highly flawed, shouldn't people take the skeptic's position?

Really? Let's say gravity, black holes, evolution, and nuclear weapons all seem weird to some skeptic. So, should we all be skeptical of that? To be clear, the skeptic has no informed reasons, and in fact the main reasons for the confusion are due to ignorance (and I guess skepticism).

I'd be interested to hear a bit more about your practical epistemological philosophy.

Evidence, and citations. And having a general grasp of at least the basic data (as well as any theories you want to argue against).
Sorry, but "I don't get it" isn't a valid counter-argument.

The only thing I agree with is that you are correct in pointing out that a layman's brain probably shuts off somewhere a few paragraphs into the technical details of this argument, and they might walk away thinking it was just too technical, so they weren't convinced. And that's fine. Remember, this thread isn't about convincing anyone. It's about discussing technical details. If you'd like to be convinced, we can start a new thread about that and talk about something with much less sketchy data than ancient Croatian toponyms.

---

Sincerely, I really wish we could move on from discussing how confusing and technical the proposed explanation for Croatian toponyms is. I agree with you! (That doesn't mean FlatAssembler is wrong: the proposal here is about as confusing and technical as I would expect for explaining ancient toponyms with limited data!)

So, anyone want to start a thread about a new or more general topic, say in the Historical Linguistics forum? This thread is meant for FlatAssembler to express ideas about a particular theory, and that is the entire purpose of this subform, "outside of the box"-- that's why it was added to the forum! (Read the rules in the sticky thread here if you'd like to know more. It was completely appropriate for FlatAssembler to post this type of thread here because this is for new and controversial ideas to be expressed/discussed.)

And to be clear, FlatAssembler should be welcome to continue discussing this theory here (again, that's the point of this sub-forum). But this thread has been dragged so far on a tangent at this point I don't know if FlatAssembler will continue to do so. (It makes me think I should revise the rules for the sub-forum so that any replies going too far off topic will simply be removed in order to let the original poster actually have a conversation about their proposal, regardless of how implausible it may seem to some. Again, that's the point of this sub-forum!)

The science is too bookish and nerdy to understand, oh no!

How can you call what FlatAssembler is doing science? He obviously won't change his mind no matter what others tell him.

And what do you mean by "technical discussion"? To me this is more like trying to hide the fact that the ideas are nonsensical by using a seemingly scientific language. We shouldn't accept something because we don't understand the arguments for it, which is what you guys seem to expect us to do. People shouldn't have accepted the pseudoscientific arguments made by the Nazis just because they hadn't understood them.

What do you mean by "scientific contribution"? What does my "scientific contribution" have to do with whether his ideas are sensical? And isn't making a blog about your pseudoscientific ideas worse than doing nothing?