Came across this passage from a letter Franz Rosenzweig sent to Hans Ehrenberg in 1918:
What does the irrational number mean in relation to the rational? For rational numbers, infinity is an always unattainable limit, a forever improbable magnitude, even if it is of the order of certainty, of permanent truth. With irrational numbers, on the contrary, at each of its points that limit comes up against rational numbers, almost physically, with the presence specific to numbers, thus liberating it from its abstract, linear and one-dimensional nature (from which its hypothetical status also proceeds), to confer a “spatial” totality and an obvious reality on it. In the form of the infinitesimal number, infinity is the secret spring, forever invisible, of the rational number and its visible reality. On the other hand, through the irrational number, infiinty is manifested, becomes visible, while forever remaining an alein reality: a number that is not a number, or so to speak a “non-number.”
What an interesting (and oddly clear) passage. It’s a rather succint statement of Rosenzweig’s conception of redemption (and critique of Hegel) and sheds a some light on how Rosenzweig approaches some of the problems towards the end of the Star, e.g. progress, messianism, election and history. Anyway, at long last I have gotten a hold of Stephane Moses’ recently translated The Angel of History: Rosenzweig, Benjamin, Scholem. Time permitting, I’m hoping to throw together some thoughts about Moses’ text and more broadly, Rosenzweig sometime soon.