When did the last original thought happen then? Clearly thoughts must have been original at some point, or there wouldn't be any at all
Did those original thoughts not build upon all the original thoughts that came before them?
Technically one of {Newton, Leibniz} was first, but you're missing GP's point
When did the first homo sapiens exist? Ideas like species evolve. Saying there are no original ideas seems to me an attempt to glibly capture something quite fundamental.