Certainly, but I think it's important to consider that the Prussian landed gentry did not utilize slaves as did the land owners of Jefferson's fellow Virginians. Jefferson's writing often show someone ahead of his time, but his actions contradicted them in many ways since he was clearly addicted to the financial security of slavery (he also owed a lot of money throughout his life). Von Humboldt had no such ties to slavery in his affairs or those of his family or Prussian neighbors.