> Can humans actually do that?

From my reading yes, but I think I am likely reading the statement differently than you are.

> from first principles

Doing things from first principles is a known strategy, so is guess and check, brute force search, and so on.

For an llm to follow a first principles strategy I would expect it to take in a body of research, come up with some first principles or guess at them, then iteratively construct and tower of reasonings/findings/experiments.

Constructing a solid tower is where things are currently improving for existing models in my mind, but when I try openai or anthropic chat interface neither do a good job for long, not independently at least.

Humans also often have a hard time with this in general it is not a skill that everyone has and I think you can be a successful scientist without ever heavily developing first principles problem solving.