Because you can successfully use it to communicate with other people. That's the grounding truth. If you'd only ever read about it and never actually employed it then yes, you would not be able to make that claim.
It's not the same thing. A language is a closed system, it just requires that the participants agree on the rules in order to be successful. Biology is not a language, it's a field of study of phenomena that exist independently of minds. If you read a biology textbook (or an LLM's output about biology) and then relate to someone else what you've read, you and the other person can discuss the topic, and be no closer to ascertain whether what you two understand has any basis in reality.
> Biology is not a language, it's a field of study of phenomena that exist independently of minds.
Your personal assertion is quite wrong at a fundamental level. Biology refers to the field or study, not individual specimens. The field is comprised of the understanding that people over time compiled on nature, along with arbitrary frameworks that help people organize and reason about the topic.
Take the concept of species, and species classification. A specimens exists regardless of being classified or not. However, the same specimen can be classified differently depending on the state of the body of knowledge at the time. In some cases you had species being reclassified due to new findings, such as genetic tests.
Once you understand this, you learn that you can't claim that a field of study is anything other than abstractions and partial and incomplete observations compiled form people throughout time.
Biology is in some sense a language, how do we even agree on what the boundaries of biology vs other domains of science are without participants agreeing on the rules?
In any case I think you have an overly narrow definition of learning that we're unlikely to come to terms over.
He's talking about learning that makes you operational. If you can speak with someone, then you've learned language. If you can get a computer to do something, then you've learned some programming.
The equivalent for biology would be to grow a plant or a few plants and animals successfully. That's operational at a certain level, you could also be operational at a lower or higher level.
No, it doesn't necessarily need to be applicable, it just needs to be testable. The size of the Earth for example may not affect you directly in any way, but it's something you can verify to some degree of precision. But if you just read about it, can you really say that you know it? What if all you believe about the size and shape of the Earth is from what you've asked an LLM? Do you still know it?
EDIT: Perhaps not the best example, because the size and shape of the Earth are data that are repeated often enough that an LLM would be unlikely to quote it grossly incorrectly, but I think my point still comes across.
I’ve been burned by this enough that I no longer say that I’ve learned something if my only interaction with it is explanation from books. You can get snippets of knowledge and a framework of understanding, but true learning only comes with deep interaction of the concepts (practice, simulation, experiments, observations) and not merely reading.
>how do we even agree on what the boundaries of biology vs other domains of science are without participants agreeing on the rules?
Those boundaries are completely imaginary and don't exist in reality. In reality there's no biology, there's only elementary particles interacting physically. Whether you agree with someone else to classify a phenomenon as biological or chemical, you're not refining your knowledge of the real world, you're just performing an organizational task.
But, say, how many times the tympanic ear evolved independently is a real phenomenon that can be investigated, and it's something that you're either correct, incorrect, or ignorant about. If I tell you it evolved five times, what more can either of us gleam about the real facts by just discussing this factoid back and forth, if neither of us has access to any additional knowledge or way to put this datum to the test?
