So Kant’s discovery was that, rather than experience the world as it’s really out there, we experience our own personalized processed version of what’s out there. Such properties as space, time, quantity, causality are in us, not out there – we impose them on reality. But, then, what is pure, unprocessed reality? What’s really out there, that raw entity before we process it? That will always remain unknowable to us, said Kant.