Gallows Man, Fact of Reason, Moral Law and Freedom

This is an informal piece of writing for PHILOS 151B taught by Prof. Dewitt at UCLA.

Kant seems to have given two very different accounts for how morality is possible in G and KpV: In both of them, he shows the biconditional between the existence of an unconditional moral law and that of freedom. But the step he takes next differs a lot between these works:

In Section III of G, Kant then tries to persuade us that we must "necessarily attribute to every rational being who has a will also the idea of freedom, under which only can such a being act" (G4:448), and then with that we would have to admit that we must attribute to ourselves of this idea of an unconditional moral law by the biconditional.

Whereas in KpV, he just asserts that "the consciousness of this unconditional moral law is a fact of reason", which "one cannot reason from antecedent data of reason." (KpV 5:31) I was confused when I read this the first time -- How can we just have a "fact of reason" without any further reasoning for it? How can Kant just claim this without any warning? Why does he switch to an entirely different order of thinking about freedom and morality?

It also seems that in this shift Kant is trying to correct his mistake, for though he was trying to show morality through our idea of freedom in the G, in KpV he suddenly starts to remind us that "assuming the freedom of the will would require an intellectual intution." Thinking in that way, we might be able to understand the motive for which Kant would like to just claim we have a fact of reason for morality. But still, that seems unplausible at first glance -- you can't just claim whatever you want to show to be a fact of reason, or otherwise I can just show anything I want as long as they are consistent! But in fact, on a second read it seems that in the preceding pages Kant did give some evidence for this fact of reason (for how we can cognize that we have this fact, but not for how we have it), and that is where the Gallows Man (KpV 5:30) comes -- Since everyone can find it not completely unreasonable to act in a way that diminishes completely the ground for happiness (and thus all the future happiness), there must be a determining ground of our will (in the general sense) that is independent from that of happiness. And thus it would then not be crazy to assert the fact of reason of moral law.

But coming back to the previous question, did Kant really make a mistake? I don't think so. He of course understands what he wrote in KrV, and he does not seem to be a careless thinker to just assert we have intellectual intuition in G. What appears to be interesting here is that in Section III of G he has always been talking about the necessity of the idea of freedom, instead of just freedom.