We know that along with all necessary humanizations of morality
there must remain in this human representation an inaccessible core
of the Prophets' God: "With whom will I compare thee, that is like
unto Thee?" In this eternal and not merely cosmological core of faith
in God, all Christians are Israelites.
I have been buried deep in historical works on the Enlightenment, paying close attention to the issue of religion and the eighteenth century (also issues of secularization). One aspect I will at least try to incorporate is the way the Enlightenment has been challenged in the last thirty years from the postmodern, postcolonial ans subaltern studies; from what I can tell, some of these works border the ahistorical and the imaginary. However, J. Kameron Carter's work Race does a good job in making the point that modern racism has its roots in supersessionism. Here is a key quote on his damning chapter on the Prussian philosopher:
For Kant, the teleological movement toward the perfect race—carried out by white ﬂesh and contrasted to the limitations of the black race—is not yet complete. Indeed, his project, I claim, from the great critical and moral philosophy, with its account of aesthetics and its teleology of culture, to his political and religious outlook, is an attempt to work out how Aufkla¨rung as humankind’s stepping out (Ausgang) of immaturity into maturity is the sociopolitical process by which the project of whiteness is to be completed as the project of reason. The reconstituted and enlightened body politic completes the task of the (perfect) ‘‘race-ing’’ of the body (90).