[czep]

> what is genuinely new and what is a rehash.

I struggled with this in grad school, as it often felt I was rereading the same material in multiple journals, and the examples of my successful peers appeared to me to be the same paper with 8 different introductions!

But the example Rota gives of Riesz is illuminating: by refining an idea over time, not simply rehashing, the product improves and eventually becomes "perfect". I think this is the original and benign intent of what has often devolved into the appearance of "publish or perish".