Literally, we could use some evidence, especially about the last sentence. Adverbs and adjectives aren't evidence.

I'm always fascinated by how humans end up discussing these things.

Like in this case, who has the burden of proof?

I'm an outsider to this field so all I can glean is that apparently the vast majority of summaries I can find cite 200-300 kYa and one reference citing an "unambiguous" find that places the technique at 400 kYa.

So if somebody says that "there doesn't seem to be enough evidence for a claim that the levallois technique is 500 kYa" (I'll soften the more incendiary phrasing of "no scientific basis whatsoever" because after all that's just an emphatic raetoric device and I think filtering them out is conducive to more fruitful discussion), do they have to back it up with references?

Or is the person who claims 500 kYa that has to provide arguments as to why that number is not yet part of the scientific consensus?

I mean, there could be simple explanations like "yes I know, the result is relatively new so you may still find a lot of references to 200-300 around until stuff gets updated but working scientists in the field are mostly on board with 500 kYa". I mean for me, a casual reader, this kind of argument would be enough for a thread of HN.

What if somebody claims that the technique is 10 million years old, and somebody replies "there is scientific data backing that up", would it be reasonable to counter that with "please provide proof for your dismissal"? Obviously not, because the claim would be so outlandish, right? But 1M, 800 kYa?

Those questions also perpetually interest me. What is the burden of proof? Whose is it and how much? Burden of proof isn't a great term, I think, because hopefully we're sort of working together, both interested in the truth.

In this case, it seems you're overlooking that I provided an actual expert, an anthropologist, who provided an answer. IMHO, amatuers' (a group that includes me) attempts to interpret evidence may be interesting, but we are highly error-prone and our offerings pointless beside expert judgment.

Also, you're not proving the negative (no reason to say 500 kya), just offering non-contradictory evidence that those tools appearing later also. Proving a negative, of course, is very difficult, but here we have an expert who apparently thinks otherwise.

It would be hard to ignore the expert because another amatuer doesn't know of any evidence for it. To prove that negative, we'd need an expert saying so - e.g., 'the evidence says it began 350 kya at the earliest'.

I think the answer is, we want comments to add value, be worth everyone's time to read. The standards of evidence will depend on what evidence is available and already posted - sometimes any shred of evidence helps; for topics drowning in misinformation, only high-quality evidence is worthwhile IMHO. Having said that, I'll have to look at mine and see if I met that standard!