Ask HN: First to Discover or First to Document?

I was reading a Wiki article on simultaneous or multiple discoveries and a lot of the stuff just sounds ridiculous. It's less of discovery and more of documentation. Was Galileo really the first person EVER to discover that both heavy and light balls fall together? I have some confidence that someone in the generations before would have noticed such but not taken it so seriously. A perfect example is David Livingstone. The guy is known to have 'discovered' the Victoria Falls. SERIOUSLY? Anyone with at least average logic can call bullshit on that. Both cases, and many others, were probably the first or so to DOCUMENT these occurences, but definitely not the ones to DISCOVER. Where does it start, where does it end? Why are we so bent on discovery rather than what it really is, documentation?