By “idea” researchers usually imply “idea for a high-impact project that I’m capable of executing”. It’s not just about having ideas, but about having ideas that will actually make an impact on your field. Those again come in two flavors: “obvious ideas” that are the logical next step in a chain of incremental improvements, but that no one yet had time or capability to implement; and “surprising ideas” that can really turn a research field upside down if it works, but is inherently a high-risk/high-reward scenario.
Speaking as a physicist, I find the truly “surprising ideas” to be quite rare but important. I get them from time to time but it can take years between. But the “obvious” ideas, sure, the more students I have the more of them I’d work on.
> Any of these ideas can be a paper, but what makes it science can't just be the fact that it was communicated clearly. It wouldn't be science unless you perform experiments (that accurately implement the "idea") and faithfully report the results. (Reviewers may add an additional constraint: that the results must look "good".)
I kinda agree with this. With the caveat that I’d consider e.g. solving theoretical problems to also count under “experiment” in this specific sentence, since science is arguably not just about gathering data but also developing a coherent understanding of it. Which is why theoretical and numerical physics count as “science”.
On the other hand, I think textbooks and review papers are crucial for science as a social process. We often have to try to consolidate the knowledge gathered from different research directions before we can move forward. That part is about clear communication more than new research.