Pretty much every single idea in science can be traced back to some combination of earlier ideas, and as they get earlier / simpler, they can be related back to some combination of direct observations.
It's not clear to me at all that our entire body of scientific knowledge can't be simply recreated by "combining results of observations + previous information". And LLMs can perform observations in addition to combine previous information, which in my estimate is genuinely sufficient for them to plausibly be able to rebuild all of science.
If every piece of knowledge is created by combining previous ones, then no true grounded knowledge is possible. Every bit of knowledge is grounded by another bit of knowledge which is itself grounded on, ..., etc, etc.