Firstness, Oneness, Noumenon

The incapacity of human knowledge to explain why humans respect Reason is not a defense of the absence, in Kant's theory, of an explanation of how that respect entails a bridging of the noumenon-phenomenon chasm.  Indeed, that absence might reflect an impossibility that refutes the posited heterogeneity of the two realms.  Instead, the difference between the realms might be one of degree, like that of the continuum between his categories of Negation and Reality, or of that between Firstness and Secondness, rather than one of kind, such as that between Oneness and Twoness.