Well, that's not what I'm arguing. What I am arguing is that lack of proof is not proof of lack - the fact that, for example, currently oldest artwork we know of is 30 000 years old does not prove that's when homo sapiens started making art and not any earlier, but instead that it proves that humans have been making art AT LEAST 30kya, AND that they must have started doing it earlier.

P.S. the 'oldest art is 30 thousand years old' bit is in the context of 'behavioral modernity' theory at the time it was posited, based on European cave art; in the meantime, we've found even older art in a cave in Indonesia (40 thousand years old).