I think it is more accurate to say that for each concept, there would be a great starting point for which they could then confirm.

Yes and no.

Remember that a large part of the reverence that we have for "the ancients" is because there was a long stretch of time during the middle ages in which old knowledge that had disappeared was rediscovered. The scholastics/etc. were all about finding old books from Greek/Roman times and learning from them, much more than creating new discoveries.

And this made sense at the time, as it would if all of our technology and knowledge were gone.