Eloi wrote: ↑Tue May 31, 2022 2:33 pmThe data may be facts, what you do with it is something different. With the same data, under different programs you can have different results. That is not objective, it is subjective.
That's not what "subjective" means. By codifying a set of rules, the process becomes objective, even if it's wrong. Maybe it's wrong. I personally don't think so, but then again, I know how it works. I'm offering to help you learn how it works, too.
Eloi wrote: ↑Tue May 31, 2022 2:33 pmIt is like I said somewhere else: you'd be building skyscrapers on quicksand.
And we're back where we started. You have no idea how any of it works, but you're utterly confident that it's wrong. Not only that, but I'm offering to teach you how it works and you're making excuses for why you don't want to learn.
Eloi wrote: ↑Tue May 31, 2022 3:05 pmAnd again: what are the criteria used by experts in taxonomically classifying a bone as belonging to a normal ape, ape-man, or a human?
Broadly, the paleontologist will take as many measurements as possible for different "characters" of the remains. When talking about a bone, these can be simple things, like absolute length, width, and their simple ratios, but also things like ratios, angles between different parts of the bone, points where muscles attached, curvatures, and things like that. If I handed you a hundred assorted chicken femurs, a hundred duck femurs, and a caliper, I'd bet that it wouldn't take you very long to come up with a list of characters that would allow you to distinguish whether the next femur I gave you came from a chicken or a duck. I found
an Open Access paper that gives a list of characters used in one particular cladistic analysis.
Eloi wrote: ↑Tue May 31, 2022 3:05 pmI can ask it in parts... For example: how would they know that a Neanderthal is not just a human who ethnically has its own characteristics, as a modern human living isolated somewhere on the planet would have, and not an ape-man as they have classified it?
It's a statistical process. If there's just one, they don't know for sure and when species are closely related, that's often the direction that scientific arguments go. Once one has a bunch of neandertal remains and a bunch of anatomically modern human remains, then one can make a statistical decision about relationships.
Neandertals aren't "ape men" by any definition, by the way. Most scientists now considert them to be the same species as modern humans,
Homo sapiens, but a different subspecies:
Homo sapiens neanderthalensis vs.
Homo sapiens sapiens.
Eloi wrote: ↑Tue May 31, 2022 3:05 pmDo they decide if it's one thing or the other just because that's what they want to believe?
Heh. I'm just going to just leave this here because it's funny.
Eloi wrote: ↑Tue May 31, 2022 3:05 pmIf I were to say that Neanderthal is just a Homo Sapiens with different ethnicity and in a different epoch, based on the fact that some modern humans have "Neanderthal" genes... could I be right?
Actually, that is already sort of right for the reason I already gave. As far as "different epoch," though, we have
Homo sapiens sapiens remains contemporary with the
neanderthalensis remains.
The crux of your question, though, is how sure can one be that you're telling the groups apart? Again, that's a statistical argument. If your list of characters is such that, say, 99% of each group fits the range of measurements, then you can be roughly 99% certain that you've at least identified which group a new specimen belongs to. Of course, there's always the question of whether or not a particular grouping was accidentally created by the researcher, particularly with closely-related species. The solution to that is to make sure that your dataset is large enough that it's statistically improbable that the measurements overlap.
That's actually the biggest benefit of molecular data. Each nucleotide or amino acid position represents a single character and each gene represents dozens or hundreds of characters. If someone else does the actual sequencing, you or I could generate a cladistic analysis based on thousands of characters in a few hours with free software and a web browser.
Eloi wrote: ↑Tue May 31, 2022 3:05 pmIsn't speciation
proportionally inverse with the possibility of reproduction between individuals under natural conditions?
I'm not
exactly sure what you mean, but the answer is "I think so." Speciation generally takes place when a population becomes two separate populations of the same species. If they're reproductively isolated from each other long enough, then they'll eventually become incompatible. This often happens with some sort of physical boundary, like happened with camels and llamas when Africa separated from South America, for example, but can also happen for other reasons, like with cichlid populations in African lakes, where different populations inhabit varying depths of the lakes.