Even if they are not "like" human brains in some sense, are they "like" brains enough to be counted similarly in a legal environment? Can you articulate the difference as something other than meat parochialism, which strikes me as arbitrary?
All law is arbitrary. Intellectual property law perhaps most of all.
Famously, the output from monkey "artists" was found to be non-copyrightable even though a monkey's brain is much more similar to ours than an LLM.
[1] https://en.wikipedia.org/wiki/Monkey_selfie_copyright_disput...
All definitions are arbitrary if you're unwilling to couch them in human experience, because humans are the ones defining. And my main difference is right there in my initial response: an LLM is a stateless function. At best, it is a snapshot of a human brain simulated on a computer, but at no point could it learn something new once deployed. This is the MOST CHARITABLE interpretation of which I don't even concede in reality, it is not even a snapshot of a brain.