Fallenness of Reason; Apologetics Can't Provide Proof

"Thus, Paul advocates a mode of public engagement that rests not on demonstration but on proclamation, not on neutral universal logos but on a particular, scandalous kerygma (1 Cor. 2:1-5). The neutral, autonomous reason that would have to underwrite a project of demonstration has been forfeited by the fall. An important consequence follows: The project of apologetics - especially 'classical apologetics' - must be seen as an illegitimate project, illegitimate not because of its goal of witness or proclamation but because of its mode. Even if one suggests that only the 'preambles of faith' (such as the existence of God, the necessity of objective moral standards, etc.) can be demonstrated by appeal to a universal, autonomous reason, one has failed to grasp the scope and ubiquity of the fall. One is unwittingly guarding a sphere of creation that is untouched by sin."

James K.A. Smith, Introducing Radical Orthodoxy, p. 180