Darwin has nothing to do with German Idealism nor idealism proper. The above essay is very wrong about Kant. Intuition --give knowledge about phenomena but nothing  a priori. But we do have a priori knowledge. That is Kant's thesis. Not only do we have a priori but also synthetic a priori. That comes from a different faculty called reason. 
But because of  the regress of reason we still need justification and that Hegel says is a kind of source of knowledge called an infinite idea which I think means and an idea gotten after an infinite process of dialectics.