Answer

A difficult question. On the philosophical plane, it seems to me that the main thing is the distinction between the analytic and the synthetic, and the connection to intuition, with all its implications. On the Jewish plane—I can’t point to one particular innovation as the main one. Narrowing down the general structure and clarifying the essence, extracting the grain from the chaff. I think there are quite a few innovations, but I can’t point to something as the most fundamental and central.
I’ll just add one general comment. It is difficult to speak about an innovation in any worldview, since every such innovation has earlier sources. Innovations belong to the one who grasped and formulated them, and not necessarily to the one who invented them.