In 1934 Emil Brunner, a theologian who had stood with Karl Barth against liberal Protestantism through the 1920s, published an essay arguing that some point of contact must exist within natural human capacity, reason, conscience or the structure of human existence itself, for God's revelation to be received at all; without it, Brunner asked, how could a person even recognize revelation as addressed to them. Barth's answer, published the same year under the single word "Nein!", German for "No!", was total. Any natural point of contact, Barth argued, however modest, smuggles back in exactly what neo-orthodoxy existed to rule out, a human capacity that revelation merely completes rather than one that revelation alone creates from nothing, since fallen human nature has no standing capacity of its own to reach toward God.
The exchange was not a minor academic disagreement between allies. It marked a real division within the movement over how absolute the break with natural theology had to be, and it arrived in the same year Barth co-authored the Barmen Declaration, rejecting the German Christian movement's attempt to read National Socialist ideology as a second source of revelation alongside scripture. The two acts shared a single conviction: that granting any independent standing to natural human insight or ideology, however plausible or however patriotic, opened a door revelation alone should occupy, and once opened, a door could be walked through toward political catastrophe as readily as toward false theology.